update release note.
update release note.

pascalberger/docfx,LordZoltan/docfx,dotnet/docfx,LordZoltan/docfx,superyyrrzz/docfx,pascalberger/docfx,superyyrrzz/docfx,hellosnow/docfx,sergey-vershinin/docfx,sergey-vershinin/docfx,928PJY/docfx,928PJY/docfx,928PJY/docfx,LordZoltan/docfx,hellosnow/docfx,hellosnow/docfx,DuncanmaMSFT/docfx,LordZoltan/docfx,sergey-vershinin/docfx,DuncanmaMSFT/docfx,dotnet/docfx,dotnet/docfx,superyyrrzz/docfx,pascalberger/docfx