Update changelog for 2.4.0.
Update changelog for 2.4.0.

lockerfish/okhttp,ChinaKim/okhttp,ijidan/okhttp,DeathPluto/okhttp,qinxiandiqi/okhttp,codelion/okhttp,wlrhnh-David/okhttp,qingsong-xu/okhttp,liqk2014/okhttp,snodnipper/okhttp,HuangWenhuan0/okhttp,yuhuayi/okhttp,LittleApple2015/okhttp,rschilling/okhttp,adithyaphilip/okhttp,Synix/okhttp,jiyiren/okhttp,ZhQYuan/okhttp,yswheye/okhttp,jituo666/okhttp,zheng1733/okhttp,jinmiao0601/okhttp,huluhaziqi/okhttp,hesy007/okhttp,tiarebalbi/okhttp,sunshinecoast/okhttp,xubuhang/okhttp,yakatak/okhttp,zmywly8866/okhttp,qinxiandiqi/okhttp,Pannarrow/okhttp,DeathPluto/okhttp,danielgomezrico/okhttp,shashankvaibhav/okhttp,VioletLife/okhttp,snodnipper/okhttp,hanlonghxp/okhttp,mikandi/okhttp,jinmiao/okhttp,huluhaziqi/okhttp,lypdemo/okhttp,VioletLife/okhttp,StarRain/okhttp,ptornhult/okhttp,HuangWenhuan0/okhttp,apoorvmahajan/okhttp,Papuh/okhttp,marenzo/okhttp,HuangWenhuan0/okhttp,tiarebalbi/okhttp,ruikong/okhttp,marcelobns/okhttp,yschimke/okhttp,sunshinecoast/okhttp,apoorvmahajan/okhttp,SashiAsakura/okhttp,Papuh/okhttp,felipecsl/okhttp,zhupengGitHub/okhttp,yswheye/okhttp,yukuoyuan/okhttp,CharlieJiang/okhttp,Eagles2F/okhttp,mgp/okhttp,icefoggy/okhttp,jokerzzzz/okhttp,wanjingyan001/okhttp,zhupengGitHub/okhttp,yangshangwei/okhttp,yangshangwei/okhttp,marcelobns/okhttp,yanqiangfire/okhttp,MichaelEvans/okhttp,LittleApple2015/okhttp,lypdemo/okhttp,xph906/NetProphet,Cryhelyxx/okhttp,nachocove/okhttp,ansman/okhttp,cketti/okhttp,damien5314/okhttp,LB6264/okhttp,PatrickDattilio/okhttp,sam-yr/okhttp,square/okhttp,SOFTPOWER1991/okhttp,wendelas/okhttp,felipecsl/okhttp,xph906/NewOKHttp,v7lin/okhttp,sam-yr/okhttp,tiarebalbi/okhttp,ysjian/okhttp,zheng1733/okhttp,ooon/okhttp,NightlyNexus/okhttp,hisery/okhttp,jiyiren/okhttp,Jinghualun/okhttp,germanattanasio/okhttp,ysjian/okhttp,ChanJLee/okhttp,yangzilong1986/okhttp,germanattanasio/okhttp,wfs3006/okhttp,airbnb/okhttp,ZhQYuan/okhttp,ptornhult/okhttp,YlJava110/okhttp,NightlyNexus/okhttp,Papuh/okhttp,jrodbx/okhttp,ze-pequeno/okhttp,zhupengGitHub/okhttp,SunnyDayDev/okhttp,marenzo/okhttp,jituo666/okhttp,artem-zinnatullin/okhttp,jokerzzzz/okhttp,liqk2014/okhttp,DeathPluto/okhttp,rschilling/okhttp,LB6264/okhttp,jfcalcerrada/okhttp,292388900/okhttp,Gaantz/okhttp,zmywly8866/okhttp,wlrhnh-David/okhttp,ptornhult/okhttp,hisery/okhttp,jovezhougang/okhttp,lobo12/okhttp,artem-zinnatullin/okhttp,cnoldtree/okhttp,jiekekeji/okhttp,bestwpw/okhttp,AmberWhiteSky/okhttp,rschilling/okhttp,ankit3005/okhttp,AmberWhiteSky/okhttp,jrodbx/okhttp,AmberWhiteSky/okhttp,wfs3006/okhttp,layerhq/okhttp,b-cuts/okhttp,SunnyDayDev/okhttp,Synix/okhttp,VikingDen/okhttp,Eagles2F/okhttp,ijidan/okhttp,KENJU/okhttp,Voxer/okhttp,germanattanasio/okhttp,ze-pequeno/okhttp,PatrickDattilio/okhttp,yangzilong1986/okhttp,mikandi/okhttp,jovezhougang/okhttp,zmarkan/okhttp,hanlonghxp/okhttp,cketti/okhttp,ankit3005/okhttp,YlJava110/okhttp,JohnTsaiAndroid/okhttp,ysjian/okhttp,JohnTsaiAndroid/okhttp,cmzy/okhttp,chaitanyajun12/okhttp,yakatak/okhttp,elijah513/okhttp,ooon/okhttp,jinmiao/okhttp,jiyiren/okhttp,StarRain/okhttp,VideoTec/okhttp,309746069/okhttp,ansman/okhttp,enlyn/okhttp,fjg1989/okhttp,jinmiao/okhttp,yangshangwei/okhttp,cketti/okhttp,zmywly8866/okhttp,icefoggy/okhttp,linyh1993/okhttp,hesy007/okhttp,wanjingyan001/okhttp,lobo12/okhttp,idelpivnitskiy/okhttp,allen0125/okhttp,junenn/okhttp,yschimke/okhttp,qingsong-xu/okhttp,teffy/okhttp,square/okhttp,enlyn/okhttp,Jinghualun/okhttp,wfxiang08/okhttp,yuhuayi/okhttp,idelpivnitskiy/okhttp,elijah513/okhttp,hgl888/okhttp,amikey/okhttp,nfuller/okhttp,NerrickT/okhttp,VikingDen/okhttp,yakatak/okhttp,layerhq/okhttp,yuhuayi/okhttp,292388900/okhttp,jfcalcerrada/okhttp,wfxiang08/okhttp,NerrickT/okhttp,LittleApple2015/okhttp,NightlyNexus/okhttp,layerhq/okhttp,danielgomezrico/okhttp,jinmiao0601/okhttp,VikingDen/okhttp,Eagles2F/okhttp,Cryhelyxx/okhttp,KENJU/okhttp,VideoTec/okhttp,SOFTPOWER1991/okhttp,zmarkan/okhttp,ChinaKim/okhttp,square/okhttp,lockerfish/okhttp,ansman/okhttp,mjbenedict/okhttp,huihui4045/okhttp,yukuoyuan/okhttp,jiekekeji/okhttp,fjg1989/okhttp,nfuller/okhttp,ChanJLee/okhttp,teffy/okhttp,enlyn/okhttp,codelion/okhttp,bestwpw/okhttp,junenn/okhttp,jituo666/okhttp,mikandi/okhttp,allen0125/okhttp,hesy007/okhttp,ijidan/okhttp,Voxer/okhttp,Pannarrow/okhttp,wendelas/okhttp,ruikong/okhttp,xuIcream/okhttp,shashankvaibhav/okhttp,SOFTPOWER1991/okhttp,codelion/okhttp,b-cuts/okhttp,wlrhnh-David/okhttp,Synix/okhttp,yanqiangfire/okhttp,StarRain/okhttp,YlJava110/okhttp,joansmith/okhttp,teffy/okhttp,jiekekeji/okhttp,cnoldtree/okhttp,v7lin/okhttp,ruhaly/okhttp,zheng1733/okhttp,hgl888/okhttp,amikey/okhttp,Pannarrow/okhttp,xubuhang/okhttp,CharlieJiang/okhttp,zmarkan/okhttp,mgp/okhttp,292388900/okhttp,liqk2014/okhttp,xph906/NewOKHttp,apoorvmahajan/okhttp,jrodbx/okhttp,lobo12/okhttp,cmzy/okhttp,xph906/NetProphet,elijah513/okhttp,PatrickDattilio/okhttp,b-cuts/okhttp,wfs3006/okhttp,minakov/okhttp,VideoTec/okhttp,wanjingyan001/okhttp,junenn/okhttp,artem-zinnatullin/okhttp,ankit3005/okhttp,xuIcream/okhttp,bestwpw/okhttp,danielgomezrico/okhttp,chaitanyajun12/okhttp,KENJU/okhttp,damien5314/okhttp,ChanJLee/okhttp,MichaelEvans/okhttp,icefoggy/okhttp,ruhaly/okhttp,tsdl2013/okhttp,xubuhang/okhttp,adithyaphilip/okhttp,SashiAsakura/okhttp,MichaelEvans/okhttp,lockerfish/okhttp,allen0125/okhttp,wfxiang08/okhttp,minakov/okhttp,nfuller/okhttp,yukuoyuan/okhttp,joansmith/okhttp,Voxer/okhttp,huluhaziqi/okhttp,yswheye/okhttp,v7lin/okhttp,sam-yr/okhttp,Cryhelyxx/okhttp,SunnyDayDev/okhttp,xph906/NetProphet,zace-yuan/okhttp,mjbenedict/okhttp,hanlonghxp/okhttp,ze-pequeno/okhttp,NerrickT/okhttp,zace-yuan/okhttp,hisery/okhttp,SashiAsakura/okhttp,Jinghualun/okhttp,wendelas/okhttp,yangzilong1986/okhttp,309746069/okhttp,snodnipper/okhttp,hgl888/okhttp,cnoldtree/okhttp,tsdl2013/okhttp,felipecsl/okhttp,minakov/okhttp,309746069/okhttp,VioletLife/okhttp,airbnb/okhttp,ruhaly/okhttp,jfcalcerrada/okhttp,huihui4045/okhttp,amikey/okhttp,jinmiao0601/okhttp,yanqiangfire/okhttp,joansmith/okhttp,Gaantz/okhttp,marcelobns/okhttp,jovezhougang/okhttp,ZhQYuan/okhttp,jokerzzzz/okhttp,sunshinecoast/okhttp,LB6264/okhttp,huihui4045/okhttp,chaitanyajun12/okhttp,JohnTsaiAndroid/okhttp,qinxiandiqi/okhttp,nachocove/okhttp,ChinaKim/okhttp,ooon/okhttp,mgp/okhttp,damien5314/okhttp,mjbenedict/okhttp,nachocove/okhttp,linyh1993/okhttp,adithyaphilip/okhttp,marenzo/okhttp,CharlieJiang/okhttp,fjg1989/okhttp,tsdl2013/okhttp,lypdemo/okhttp,airbnb/okhttp,linyh1993/okhttp,xph906/NewOKHttp,shashankvaibhav/okhttp,xuIcream/okhttp,apoorvmahajan/okhttp,idelpivnitskiy/okhttp,Gaantz/okhttp,zace-yuan/okhttp,yschimke/okhttp,qingsong-xu/okhttp,ruikong/okhttp