xplat-master:

• msbuild PR for the update ([mono] Update to track upstream master msbuild#108)
• msbuild - update SDKs ([mono] Update SDKs to track cli branch release/2.1.8xx msbuild#110)
• mono bump + nuget version bump(?) (Bump msbuild to track xplat-master #14814)

2019-06:

• mono PR to track xplat-master (no separate branch for now) ([2019-06] Bump msbuild to track xplat-master #14816)
  • nuget.py bump
• Ensure that roslyn is also bumped
• Update version (https://github.com/mono/website/blob/gh-pages/docs/about-mono/versioning.md) (Update msbuild version for 2019-06 website#447)