Change version from 1.2.0 to 1.2.0-beta.
Merge pull request dotnet#1095 from sergeybykov/feature-serializer-kn… …owntype Fixed CodeGen: Allow [KnownType] & [KnownAssembly] hints, fix AssemblyProcessor scanning
Merge pull request dotnet#980 from sergeybykov/beta1 Preparations for publishing 1.1.0-beta1