Change pipe checksum to SHA256
Change pipe checksum to SHA256

Change our pipe hashing to SHA256 instead of SHA1.

The use of the SHA1 algorithm in security sensitive situations is
banned.  It is still fine as a simple check summing mechanism for public
data (as we are doing in this case).  But source code scanners can't
understand context and raise warnings whenever it is used at all.  Hence
switching this to SHA256 instead.

AmadeusW/roslyn,jmarolf/roslyn,budcribar/roslyn,MavenRain/roslyn,balajikris/roslyn,tvand7093/roslyn,enginekit/roslyn,Maxwe11/roslyn,3F/roslyn,mmitche/roslyn,bbarry/roslyn,dpoeschl/roslyn,sharadagrawal/Roslyn,a-ctor/roslyn,vslsnap/roslyn,natidea/roslyn,xoofx/roslyn,TyOverby/roslyn,physhi/roslyn,ilyes14/roslyn,Giten2004/roslyn,akrisiun/roslyn,mattscheffer/roslyn,robinsedlaczek/roslyn,jbhensley/roslyn,Pvlerick/roslyn,Giten2004/roslyn,MihaMarkic/roslyn-prank,droyad/roslyn,AArnott/roslyn,reaction1989/roslyn,antiufo/roslyn,BugraC/roslyn,tmeschter/roslyn,ErikSchierboom/roslyn,Hosch250/roslyn,bbarry/roslyn,hanu412/roslyn,RipCurrent/roslyn,CaptainHayashi/roslyn,Hosch250/roslyn,Shiney/roslyn,russpowers/roslyn,stjeong/roslyn,kelltrick/roslyn,a-ctor/roslyn,jeffanders/roslyn,paulvanbrenk/roslyn,YOTOV-LIMITED/roslyn,ahmedshuhel/roslyn,davkean/roslyn,supriyantomaftuh/roslyn,shyamnamboodiripad/roslyn,tannergooding/roslyn,YOTOV-LIMITED/roslyn,MavenRain/roslyn,cybernet14/roslyn,gafter/roslyn,enginekit/roslyn,cston/roslyn,MattWindsor91/roslyn,stephentoub/roslyn,xoofx/roslyn,aanshibudhiraja/Roslyn,ahmedshuhel/roslyn,KevinH-MS/roslyn,poizan42/roslyn,MatthieuMEZIL/roslyn,natgla/roslyn,tmeschter/roslyn,shyamnamboodiripad/roslyn,KirillOsenkov/roslyn,vslsnap/roslyn,eriawan/roslyn,michalhosala/roslyn,JakeGinnivan/roslyn,furesoft/roslyn,michalhosala/roslyn,MichalStrehovsky/roslyn,reaction1989/roslyn,AnthonyDGreen/roslyn,CyrusNajmabadi/roslyn,michalhosala/roslyn,jeremymeng/roslyn,CyrusNajmabadi/roslyn,tsdl2013/roslyn,khellang/roslyn,doconnell565/roslyn,oberxon/roslyn,MihaMarkic/roslyn-prank,CyrusNajmabadi/roslyn,VSadov/roslyn,brettfo/roslyn,managed-commons/roslyn,drognanar/roslyn,oocx/roslyn,yjfxfjch/roslyn,wvdd007/roslyn,Inverness/roslyn,evilc0des/roslyn,ValentinRueda/roslyn,rchande/roslyn,AArnott/roslyn,russpowers/roslyn,ErikSchierboom/roslyn,genlu/roslyn,KamalRathnayake/roslyn,swaroop-sridhar/roslyn,mattscheffer/roslyn,moozzyk/roslyn,srivatsn/roslyn,leppie/roslyn,cston/roslyn,OmniSharp/roslyn,balajikris/roslyn,evilc0des/roslyn,droyad/roslyn,diryboy/roslyn,heejaechang/roslyn,DinoV/roslyn,tang7526/roslyn,pdelvo/roslyn,BugraC/roslyn,HellBrick/roslyn,stephentoub/roslyn,mattwar/roslyn,sharadagrawal/TestProject2,Pvlerick/roslyn,khellang/roslyn,jkotas/roslyn,kuhlenh/roslyn,huoxudong125/roslyn,zmaruo/roslyn,tmeschter/roslyn,davkean/roslyn,jeremymeng/roslyn,agocke/roslyn,orthoxerox/roslyn,jonatassaraiva/roslyn,poizan42/roslyn,FICTURE7/roslyn,nemec/roslyn,v-codeel/roslyn,nemec/roslyn,3F/roslyn,garryforreg/roslyn,managed-commons/roslyn,ErikSchierboom/roslyn,taylorjonl/roslyn,lisong521/roslyn,mgoertz-msft/roslyn,ericfe-ms/roslyn,YOTOV-LIMITED/roslyn,DustinCampbell/roslyn,dotnet/roslyn,jbhensley/roslyn,AnthonyDGreen/roslyn,xasx/roslyn,jcouv/roslyn,akrisiun/roslyn,magicbing/roslyn,stjeong/roslyn,panopticoncentral/roslyn,TyOverby/roslyn,srivatsn/roslyn,jamesqo/roslyn,jaredpar/roslyn,sharwell/roslyn,SeriaWei/roslyn,kienct89/roslyn,doconnell565/roslyn,zooba/roslyn,oberxon/roslyn,mirhagk/roslyn,HellBrick/roslyn,jaredpar/roslyn,KiloBravoLima/roslyn,tmat/roslyn,Giftednewt/roslyn,oocx/roslyn,zmaruo/roslyn,GuilhermeSa/roslyn,orthoxerox/roslyn,brettfo/roslyn,OmniSharp/roslyn,mmitche/roslyn,TyOverby/roslyn,sharadagrawal/Roslyn,genlu/roslyn,ljw1004/roslyn,amcasey/roslyn,sharwell/roslyn,jaredpar/roslyn,jeffanders/roslyn,yjfxfjch/roslyn,tang7526/roslyn,mattwar/roslyn,gafter/roslyn,natgla/roslyn,oberxon/roslyn,MattWindsor91/roslyn,OmarTawfik/roslyn,tannergooding/roslyn,panopticoncentral/roslyn,doconnell565/roslyn,dpoeschl/roslyn,tmat/roslyn,VShangxiao/roslyn,grianggrai/roslyn,jroggeman/roslyn,orthoxerox/roslyn,drognanar/roslyn,oocx/roslyn,jrharmon/roslyn,Hosch250/roslyn,managed-commons/roslyn,DanielRosenwasser/roslyn,AdamSpeight2008/roslyn-AdamSpeight2008,mattscheffer/roslyn,aanshibudhiraja/Roslyn,kelltrick/roslyn,mgoertz-msft/roslyn,KashishArora/Roslyn,OmniSharp/roslyn,russpowers/roslyn,dotnet/roslyn,brettfo/roslyn,JakeGinnivan/roslyn,yjfxfjch/roslyn,wvdd007/roslyn,REALTOBIZ/roslyn,supriyantomaftuh/roslyn,heejaechang/roslyn,krishnarajbb/roslyn,paulvanbrenk/roslyn,droyad/roslyn,AdamSpeight2008/roslyn-AdamSpeight2008,enginekit/roslyn,v-codeel/roslyn,dovzhikova/roslyn,AlekseyTs/roslyn,krishnarajbb/roslyn,diryboy/roslyn,devharis/roslyn,jeremymeng/roslyn,jasonmalinowski/roslyn,rgani/roslyn,danielcweber/roslyn,kelltrick/roslyn,vcsjones/roslyn,mirhagk/roslyn,jbhensley/roslyn,jamesqo/roslyn,MattWindsor91/roslyn,basoundr/roslyn,Maxwe11/roslyn,Pvlerick/roslyn,bbarry/roslyn,jroggeman/roslyn,Giftednewt/roslyn,jasonmalinowski/roslyn,SeriaWei/roslyn,mavasani/roslyn,nagyistoce/roslyn,evilc0des/roslyn,amcasey/roslyn,wvdd007/roslyn,hanu412/roslyn,poizan42/roslyn,weltkante/roslyn,thomaslevesque/roslyn,DanielRosenwasser/roslyn,magicbing/roslyn,lorcanmooney/roslyn,VPashkov/roslyn,cybernet14/roslyn,mattwar/roslyn,EricArndt/roslyn,kuhlenh/roslyn,Maxwe11/roslyn,davkean/roslyn,vslsnap/roslyn,mmitche/roslyn,jamesqo/roslyn,physhi/roslyn,nemec/roslyn,bkoelman/roslyn,AlexisArce/roslyn,jcouv/roslyn,heejaechang/roslyn,sharadagrawal/TestProject2,pjmagee/roslyn,swaroop-sridhar/roslyn,pdelvo/roslyn,sharwell/roslyn,REALTOBIZ/roslyn,MavenRain/roslyn,Shiney/roslyn,KiloBravoLima/roslyn,VShangxiao/roslyn,KevinH-MS/roslyn,tvand7093/roslyn,KashishArora/Roslyn,zooba/roslyn,KamalRathnayake/roslyn,lisong521/roslyn,stebet/roslyn,MichalStrehovsky/roslyn,natgla/roslyn,robinsedlaczek/roslyn,tsdl2013/roslyn,jroggeman/roslyn,huoxudong125/roslyn,DustinCampbell/roslyn,bkoelman/roslyn,rchande/roslyn,bkoelman/roslyn,KiloBravoLima/roslyn,MattWindsor91/roslyn,nguerrera/roslyn,natidea/roslyn,kuhlenh/roslyn,DanielRosenwasser/roslyn,nagyistoce/roslyn,tsdl2013/roslyn,lorcanmooney/roslyn,moozzyk/roslyn,danielcweber/roslyn,nagyistoce/roslyn,mgoertz-msft/roslyn,basoundr/roslyn,CaptainHayashi/roslyn,jonatassaraiva/roslyn,AmadeusW/roslyn,gafter/roslyn,balajikris/roslyn,Shiney/roslyn,GuilhermeSa/roslyn,genlu/roslyn,abock/roslyn,antiufo/roslyn,DinoV/roslyn,pdelvo/roslyn,GuilhermeSa/roslyn,weltkante/roslyn,EricArndt/roslyn,ValentinRueda/roslyn,jrharmon/roslyn,khyperia/roslyn,FICTURE7/roslyn,supriyantomaftuh/roslyn,REALTOBIZ/roslyn,stebet/roslyn,jrharmon/roslyn,nguerrera/roslyn,mseamari/Stuff,magicbing/roslyn,stjeong/roslyn,rchande/roslyn,mavasani/roslyn,garryforreg/roslyn,basoundr/roslyn,srivatsn/roslyn,eriawan/roslyn,KashishArora/Roslyn,pjmagee/roslyn,ericfe-ms/roslyn,dpoeschl/roslyn,CaptainHayashi/roslyn,OmarTawfik/roslyn,antonssonj/roslyn,dovzhikova/roslyn,stephentoub/roslyn,dotnet/roslyn,ahmedshuhel/roslyn,SeriaWei/roslyn,natidea/roslyn,VitalyTVA/roslyn,kienct89/roslyn,KevinRansom/roslyn,tmat/roslyn,Inverness/roslyn,jasonmalinowski/roslyn,chenxizhang/roslyn,xasx/roslyn,abock/roslyn,Giftednewt/roslyn,khyperia/roslyn,bartdesmet/roslyn,danielcweber/roslyn,devharis/roslyn,jonatassaraiva/roslyn,taylorjonl/roslyn,jhendrixMSFT/roslyn,MichalStrehovsky/roslyn,khellang/roslyn,aelij/roslyn,bartdesmet/roslyn,thomaslevesque/roslyn,abock/roslyn,yeaicc/roslyn,mirhagk/roslyn,mseamari/Stuff,dovzhikova/roslyn,krishnarajbb/roslyn,garryforreg/roslyn,lorcanmooney/roslyn,amcasey/roslyn,a-ctor/roslyn,KirillOsenkov/roslyn,jmarolf/roslyn,DinoV/roslyn,Inverness/roslyn,DustinCampbell/roslyn,MatthieuMEZIL/roslyn,jhendrixMSFT/roslyn,shyamnamboodiripad/roslyn,AnthonyDGreen/roslyn,VSadov/roslyn,physhi/roslyn,antiufo/roslyn,tvand7093/roslyn,stebet/roslyn,Giten2004/roslyn,VPashkov/roslyn,VitalyTVA/roslyn,akrisiun/roslyn,zmaruo/roslyn,huoxudong125/roslyn,xasx/roslyn,hanu412/roslyn,jmarolf/roslyn,jkotas/roslyn,xoofx/roslyn,lisong521/roslyn,jhendrixMSFT/roslyn,antonssonj/roslyn,3F/roslyn,kienct89/roslyn,chenxizhang/roslyn,vcsjones/roslyn,leppie/roslyn,sharadagrawal/Roslyn,moozzyk/roslyn,nguerrera/roslyn,khyperia/roslyn,leppie/roslyn,aelij/roslyn,v-codeel/roslyn,devharis/roslyn,AlekseyTs/roslyn,ValentinRueda/roslyn,jkotas/roslyn,KevinH-MS/roslyn,AArnott/roslyn,budcribar/roslyn,budcribar/roslyn,paulvanbrenk/roslyn,cybernet14/roslyn,agocke/roslyn,panopticoncentral/roslyn,taylorjonl/roslyn,antonssonj/roslyn,mseamari/Stuff,VitalyTVA/roslyn,ljw1004/roslyn,reaction1989/roslyn,RipCurrent/roslyn,swaroop-sridhar/roslyn,drognanar/roslyn,OmarTawfik/roslyn,tannergooding/roslyn,MatthieuMEZIL/roslyn,jeffanders/roslyn,eriawan/roslyn,KevinRansom/roslyn,FICTURE7/roslyn,VShangxiao/roslyn,weltkante/roslyn,chenxizhang/roslyn,grianggrai/roslyn,KevinRansom/roslyn,HellBrick/roslyn,AmadeusW/roslyn,RipCurrent/roslyn,pjmagee/roslyn,diryboy/roslyn,ilyes14/roslyn,ljw1004/roslyn,KamalRathnayake/roslyn,AlekseyTs/roslyn,thomaslevesque/roslyn,jcouv/roslyn,BugraC/roslyn,AlexisArce/roslyn,VSadov/roslyn,robinsedlaczek/roslyn,AlexisArce/roslyn,vcsjones/roslyn,AdamSpeight2008/roslyn-AdamSpeight2008,cston/roslyn,EricArndt/roslyn,rgani/roslyn,MihaMarkic/roslyn-prank,zooba/roslyn,ilyes14/roslyn,yeaicc/roslyn,aelij/roslyn,grianggrai/roslyn,JakeGinnivan/roslyn,rgani/roslyn,furesoft/roslyn,yeaicc/roslyn,agocke/roslyn,sharadagrawal/TestProject2,tang7526/roslyn,ericfe-ms/roslyn,KirillOsenkov/roslyn,bartdesmet/roslyn,VPashkov/roslyn,mavasani/roslyn,aanshibudhiraja/Roslyn,furesoft/roslyn