Generate changelog / Revert remove old runtimes (#2692) * Revert remove old runtimes. * SuppressTfmSupportBuildWarnings in generated projects. Updated MultipleFrameworks tests. * Unrevert EnvRequirement.DotNetCore30Only * Fix test * PR feedback. * Some more reverts. * Fix github actions error.

Generate changelog / Revert remove old runtimes (#2692) * Revert remove old runtimes. * SuppressTfmSupportBuildWarnings in generated projects. Updated MultipleFrameworks tests. * Unrevert EnvRequirement.DotNetCore30Only * Fix test * PR feedback. * Some more reverts. * Fix github actions error. #195