Added release notes for 5.0.0-alpha4
Added release notes for 5.0.0-alpha4

JervyShi/elasticsearch,dongjoon-hyun/elasticsearch,henakamaMSFT/elasticsearch,artnowo/elasticsearch,a2lin/elasticsearch,JSCooke/elasticsearch,GlenRSmith/elasticsearch,winstonewert/elasticsearch,strapdata/elassandra5-rc,a2lin/elasticsearch,mjason3/elasticsearch,dpursehouse/elasticsearch,Shepard1212/elasticsearch,zkidkid/elasticsearch,rlugojr/elasticsearch,markwalkom/elasticsearch,mortonsykes/elasticsearch,Helen-Zhao/elasticsearch,nknize/elasticsearch,glefloch/elasticsearch,qwerty4030/elasticsearch,yanjunh/elasticsearch,JSCooke/elasticsearch,kalimatas/elasticsearch,mikemccand/elasticsearch,mjason3/elasticsearch,girirajsharma/elasticsearch,mikemccand/elasticsearch,markwalkom/elasticsearch,markwalkom/elasticsearch,MisterAndersen/elasticsearch,gingerwizard/elasticsearch,C-Bish/elasticsearch,fernandozhu/elasticsearch,bawse/elasticsearch,nazarewk/elasticsearch,gingerwizard/elasticsearch,cwurm/elasticsearch,avikurapati/elasticsearch,scottsom/elasticsearch,LeoYao/elasticsearch,sreeramjayan/elasticsearch,uschindler/elasticsearch,rajanm/elasticsearch,wangtuo/elasticsearch,strapdata/elassandra,henakamaMSFT/elasticsearch,avikurapati/elasticsearch,awislowski/elasticsearch,StefanGor/elasticsearch,nknize/elasticsearch,LeoYao/elasticsearch,MaineC/elasticsearch,palecur/elasticsearch,qwerty4030/elasticsearch,liweinan0423/elasticsearch,awislowski/elasticsearch,coding0011/elasticsearch,maddin2016/elasticsearch,Stacey-Gammon/elasticsearch,awislowski/elasticsearch,IanvsPoplicola/elasticsearch,scorpionvicky/elasticsearch,dpursehouse/elasticsearch,fforbeck/elasticsearch,C-Bish/elasticsearch,LewayneNaidoo/elasticsearch,jprante/elasticsearch,wangtuo/elasticsearch,henakamaMSFT/elasticsearch,shreejay/elasticsearch,mohit/elasticsearch,JackyMai/elasticsearch,umeshdangat/elasticsearch,MaineC/elasticsearch,shreejay/elasticsearch,vroyer/elasticassandra,wuranbo/elasticsearch,fforbeck/elasticsearch,Stacey-Gammon/elasticsearch,ZTE-PaaS/elasticsearch,yanjunh/elasticsearch,gfyoung/elasticsearch,gfyoung/elasticsearch,geidies/elasticsearch,maddin2016/elasticsearch,geidies/elasticsearch,alexshadow007/elasticsearch,wangtuo/elasticsearch,geidies/elasticsearch,StefanGor/elasticsearch,obourgain/elasticsearch,sneivandt/elasticsearch,Shepard1212/elasticsearch,girirajsharma/elasticsearch,scorpionvicky/elasticsearch,rlugojr/elasticsearch,artnowo/elasticsearch,sreeramjayan/elasticsearch,HonzaKral/elasticsearch,wuranbo/elasticsearch,HonzaKral/elasticsearch,wuranbo/elasticsearch,wenpos/elasticsearch,wuranbo/elasticsearch,ricardocerq/elasticsearch,gfyoung/elasticsearch,ZTE-PaaS/elasticsearch,ricardocerq/elasticsearch,umeshdangat/elasticsearch,kalimatas/elasticsearch,uschindler/elasticsearch,gingerwizard/elasticsearch,LewayneNaidoo/elasticsearch,rlugojr/elasticsearch,awislowski/elasticsearch,GlenRSmith/elasticsearch,sneivandt/elasticsearch,naveenhooda2000/elasticsearch,vroyer/elasticassandra,gfyoung/elasticsearch,nazarewk/elasticsearch,jimczi/elasticsearch,Stacey-Gammon/elasticsearch,gingerwizard/elasticsearch,C-Bish/elasticsearch,njlawton/elasticsearch,liweinan0423/elasticsearch,GlenRSmith/elasticsearch,s1monw/elasticsearch,avikurapati/elasticsearch,jimczi/elasticsearch,i-am-Nathan/elasticsearch,pozhidaevak/elasticsearch,spiegela/elasticsearch,robin13/elasticsearch,geidies/elasticsearch,Shepard1212/elasticsearch,nknize/elasticsearch,ZTE-PaaS/elasticsearch,nilabhsagar/elasticsearch,avikurapati/elasticsearch,MaineC/elasticsearch,vroyer/elassandra,mortonsykes/elasticsearch,coding0011/elasticsearch,strapdata/elassandra5-rc,MisterAndersen/elasticsearch,shreejay/elasticsearch,kalimatas/elasticsearch,liweinan0423/elasticsearch,sreeramjayan/elasticsearch,obourgain/elasticsearch,palecur/elasticsearch,ZTE-PaaS/elasticsearch,yanjunh/elasticsearch,sreeramjayan/elasticsearch,mohit/elasticsearch,wangtuo/elasticsearch,wuranbo/elasticsearch,pozhidaevak/elasticsearch,brandonkearby/elasticsearch,elasticdog/elasticsearch,scorpionvicky/elasticsearch,JervyShi/elasticsearch,liweinan0423/elasticsearch,alexshadow007/elasticsearch,gingerwizard/elasticsearch,MisterAndersen/elasticsearch,brandonkearby/elasticsearch,zkidkid/elasticsearch,maddin2016/elasticsearch,scottsom/elasticsearch,lks21c/elasticsearch,LeoYao/elasticsearch,Stacey-Gammon/elasticsearch,fred84/elasticsearch,LewayneNaidoo/elasticsearch,rajanm/elasticsearch,sneivandt/elasticsearch,i-am-Nathan/elasticsearch,alexshadow007/elasticsearch,coding0011/elasticsearch,spiegela/elasticsearch,Helen-Zhao/elasticsearch,Shepard1212/elasticsearch,girirajsharma/elasticsearch,ricardocerq/elasticsearch,mohit/elasticsearch,lks21c/elasticsearch,JervyShi/elasticsearch,masaruh/elasticsearch,ThiagoGarciaAlves/elasticsearch,elasticdog/elasticsearch,girirajsharma/elasticsearch,JervyShi/elasticsearch,scottsom/elasticsearch,a2lin/elasticsearch,artnowo/elasticsearch,JackyMai/elasticsearch,MaineC/elasticsearch,rlugojr/elasticsearch,obourgain/elasticsearch,mjason3/elasticsearch,jprante/elasticsearch,girirajsharma/elasticsearch,JackyMai/elasticsearch,nazarewk/elasticsearch,masaruh/elasticsearch,bawse/elasticsearch,ricardocerq/elasticsearch,JackyMai/elasticsearch,LewayneNaidoo/elasticsearch,HonzaKral/elasticsearch,naveenhooda2000/elasticsearch,robin13/elasticsearch,brandonkearby/elasticsearch,cwurm/elasticsearch,strapdata/elassandra5-rc,vroyer/elassandra,masaruh/elasticsearch,brandonkearby/elasticsearch,JSCooke/elasticsearch,jprante/elasticsearch,mjason3/elasticsearch,qwerty4030/elasticsearch,fernandozhu/elasticsearch,nezirus/elasticsearch,fforbeck/elasticsearch,a2lin/elasticsearch,scorpionvicky/elasticsearch,rajanm/elasticsearch,mortonsykes/elasticsearch,wenpos/elasticsearch,fred84/elasticsearch,rlugojr/elasticsearch,brandonkearby/elasticsearch,mikemccand/elasticsearch,umeshdangat/elasticsearch,mjason3/elasticsearch,gmarz/elasticsearch,fred84/elasticsearch,maddin2016/elasticsearch,ZTE-PaaS/elasticsearch,fernandozhu/elasticsearch,markwalkom/elasticsearch,masaruh/elasticsearch,StefanGor/elasticsearch,dpursehouse/elasticsearch,nazarewk/elasticsearch,nilabhsagar/elasticsearch,palecur/elasticsearch,elasticdog/elasticsearch,kalimatas/elasticsearch,glefloch/elasticsearch,yanjunh/elasticsearch,elasticdog/elasticsearch,coding0011/elasticsearch,s1monw/elasticsearch,girirajsharma/elasticsearch,rajanm/elasticsearch,elasticdog/elasticsearch,robin13/elasticsearch,bawse/elasticsearch,fforbeck/elasticsearch,MisterAndersen/elasticsearch,fred84/elasticsearch,uschindler/elasticsearch,geidies/elasticsearch,nezirus/elasticsearch,fernandozhu/elasticsearch,strapdata/elassandra5-rc,gmarz/elasticsearch,naveenhooda2000/elasticsearch,sreeramjayan/elasticsearch,naveenhooda2000/elasticsearch,sreeramjayan/elasticsearch,scottsom/elasticsearch,njlawton/elasticsearch,strapdata/elassandra,lks21c/elasticsearch,HonzaKral/elasticsearch,glefloch/elasticsearch,IanvsPoplicola/elasticsearch,jprante/elasticsearch,yanjunh/elasticsearch,wangtuo/elasticsearch,alexshadow007/elasticsearch,sneivandt/elasticsearch,artnowo/elasticsearch,mikemccand/elasticsearch,Stacey-Gammon/elasticsearch,njlawton/elasticsearch,nezirus/elasticsearch,markwalkom/elasticsearch,fernandozhu/elasticsearch,awislowski/elasticsearch,cwurm/elasticsearch,IanvsPoplicola/elasticsearch,scorpionvicky/elasticsearch,winstonewert/elasticsearch,gingerwizard/elasticsearch,JervyShi/elasticsearch,Helen-Zhao/elasticsearch,nknize/elasticsearch,robin13/elasticsearch,i-am-Nathan/elasticsearch,robin13/elasticsearch,MaineC/elasticsearch,zkidkid/elasticsearch,strapdata/elassandra5-rc,rajanm/elasticsearch,dongjoon-hyun/elasticsearch,qwerty4030/elasticsearch,mortonsykes/elasticsearch,C-Bish/elasticsearch,nezirus/elasticsearch,mikemccand/elasticsearch,wenpos/elasticsearch,mohit/elasticsearch,palecur/elasticsearch,JSCooke/elasticsearch,cwurm/elasticsearch,strapdata/elassandra,nknize/elasticsearch,bawse/elasticsearch,LeoYao/elasticsearch,dongjoon-hyun/elasticsearch,gmarz/elasticsearch,nilabhsagar/elasticsearch,henakamaMSFT/elasticsearch,spiegela/elasticsearch,masaruh/elasticsearch,palecur/elasticsearch,strapdata/elassandra,LeoYao/elasticsearch,njlawton/elasticsearch,MisterAndersen/elasticsearch,LeoYao/elasticsearch,JervyShi/elasticsearch,lks21c/elasticsearch,StefanGor/elasticsearch,njlawton/elasticsearch,dongjoon-hyun/elasticsearch,s1monw/elasticsearch,uschindler/elasticsearch,dpursehouse/elasticsearch,maddin2016/elasticsearch,nazarewk/elasticsearch,pozhidaevak/elasticsearch,glefloch/elasticsearch,scottsom/elasticsearch,shreejay/elasticsearch,IanvsPoplicola/elasticsearch,s1monw/elasticsearch,pozhidaevak/elasticsearch,fforbeck/elasticsearch,spiegela/elasticsearch,GlenRSmith/elasticsearch,cwurm/elasticsearch,ricardocerq/elasticsearch,Helen-Zhao/elasticsearch,jimczi/elasticsearch,jimczi/elasticsearch,vroyer/elassandra,geidies/elasticsearch,zkidkid/elasticsearch,kalimatas/elasticsearch,dpursehouse/elasticsearch,obourgain/elasticsearch,sneivandt/elasticsearch,winstonewert/elasticsearch,IanvsPoplicola/elasticsearch,ThiagoGarciaAlves/elasticsearch,ThiagoGarciaAlves/elasticsearch,gfyoung/elasticsearch,gingerwizard/elasticsearch,nezirus/elasticsearch,ThiagoGarciaAlves/elasticsearch,avikurapati/elasticsearch,jimczi/elasticsearch,wenpos/elasticsearch,JSCooke/elasticsearch,GlenRSmith/elasticsearch,gmarz/elasticsearch,nilabhsagar/elasticsearch,zkidkid/elasticsearch,henakamaMSFT/elasticsearch,C-Bish/elasticsearch,rajanm/elasticsearch,uschindler/elasticsearch,umeshdangat/elasticsearch,i-am-Nathan/elasticsearch,markwalkom/elasticsearch,jprante/elasticsearch,liweinan0423/elasticsearch,mortonsykes/elasticsearch,obourgain/elasticsearch,winstonewert/elasticsearch,JackyMai/elasticsearch,nilabhsagar/elasticsearch,umeshdangat/elasticsearch,strapdata/elassandra,fred84/elasticsearch,gmarz/elasticsearch,ThiagoGarciaAlves/elasticsearch,winstonewert/elasticsearch,lks21c/elasticsearch,LewayneNaidoo/elasticsearch,wenpos/elasticsearch,i-am-Nathan/elasticsearch,StefanGor/elasticsearch,Helen-Zhao/elasticsearch,alexshadow007/elasticsearch,shreejay/elasticsearch,pozhidaevak/elasticsearch,s1monw/elasticsearch,spiegela/elasticsearch,bawse/elasticsearch,mohit/elasticsearch,artnowo/elasticsearch,Shepard1212/elasticsearch,qwerty4030/elasticsearch,ThiagoGarciaAlves/elasticsearch,a2lin/elasticsearch,coding0011/elasticsearch,glefloch/elasticsearch,vroyer/elasticassandra,dongjoon-hyun/elasticsearch,LeoYao/elasticsearch,naveenhooda2000/elasticsearch