liblcm: make the feature/nuget branch the main development branch

[ermshiperete]

• merge master into feature/nuget again
• announce that the merge of the feature/nuget branch will be made the main development branch
• create a git tag on master (pre-nuget ?) before doing the merge
• merge feature/nuget into master. Doing this requires adjusting the path to the CHANGELOG.md file in the .csproj as well as adjusting GitVersion.yml (removing settings for feature/nuget branch).
• create a release of the nuget packages, and use these released nuget packages in the other projects.

[tombogle]

The PR represents my attempt at merging master into feature/nuget: sillsdev/liblcm#164
I was getting three test failures on my local machine, but it looks like two of them were red herrings. The third - which is a test I changed to get it to build - appears to be a new failure on the CI build. Probably someone more familiar with this project and this test should look at it and figure out the correct solution. With the WS test failure happening in libpalaso, it's entirely possible that this failure here is actually a consequence of whatever has gone wrong there, so maybe fixing this issue will set things right.