Try to use GitInfo

[dellis1972]

So lets' use the GitInfo NuGet Package to generate the required version information for Java.Interop.
The base version is controlled from GitInfo.txt. This is where the version should be edited.
The NuGet keeps track of the number of commits made since the GitInfo.txt was changed. So unless there is a major version
change (or you run out of numbers) there should be no need to alter the version on a regular basis.

All of the projects in the repo will then pick up the same version information was we will set the MSBuild Version property as well as the InformationalVersion. The latter will contain the git commit and branch.

[dellis1972]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[dellis1972]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[jonathanpeppers]

It looks like the values made it to Java.Interop.dll:

[assembly: AssemblyFileVersion("0.1.4.0")]
[assembly: AssemblyInformationalVersion("0.1.4; git-head: 11d3136 git-branch: undefined")]

Do we need to check it doesn't say undefined after we merge?

[dellis1972]

It looks like the values made it to Java.Interop.dll:

[assembly: AssemblyFileVersion("0.1.4.0")]
[assembly: AssemblyInformationalVersion("0.1.4; git-head: 11d3136 git-branch: undefined")]

Do we need to check it doesn't say undefined after we merge?

It says versioninfo_git locally. I suspect its undefined because CI does a merge commit , so its a detached head.

[jonpryor]

So a question had been "why is this PR getting CS8400 errors about interpolated strings on .NET 6 P7, but other PRs aren't?"

The answer: other PRs are now failing with CS8400 errors: https://github.com/xamarin/java.interop/pull/868/checks?check_run_id=3365711885

Not sure why there was an apparent delay. :-/

[jonpryor]

[build] Use GitInfo to generate $(Version) (#865)

Context: http://github.com/xamarin/xamarin-android/commit/2d81740cc1c708cd0474c9eac8936cd7abfc72e3
Context: https://github.com/xamarin/xamarin-android/issues/5749

In order to better support building solutions which reference both
.NET 6 and legacy projects within Visual Studio, we have begun
strong-naming all the MSBuild-related assemblies; see also ff271420.
This allows loading two different version of the "same" assembly, e.g.
`Java.Interop.Tools.Diagnostics.dll`, from two different filesystem
locations in the same AppDomain/AssemblyLoadContext.

However, strong-naming is only part of the solution.  The other part
is that, for sanity and reliability, the "two different versions of
the 'same' assembly" should *also* have different assembly *versions*.
If they have the same assembly version, are they truly different?

Update the build system by adding a `Directory.Build.targets` and
`GitInfo.txt` file so that the the [`GitInfo`][0] [NuGet Package][1]
will be used to "fully" set the `$(Version)` MSBuild property,
consisting of the major and minor version numbers contained within
`GitInfo.txt`, along with a "computed" `$(GitSemVerPatch)` value
based on the "patch version" in `GitInfo.txt`, if present, added to
the number of commits which have occurred since `GitInfo.txt` changed.

Additionally, set the `$(InformationalVersion)` MSBuild property so
that it mirrors the behavior in [`Mono.Android.dll`][2]:

	[assembly: System.Reflection.AssemblyInformationalVersionAttribute("0.1.1; git-rev-head:2eb9ff2; git-branch:main")

Setting the `$(Version)` and `$(InformationalVersion)` MSBuild
properties also requires setting `$(GenerateAssemblyInfo)`=True.
Update `src/Java.Interop/Properties/AssemblyInfo.cs` to remove the
attributes that `$(GenerateAssemblyInfo)` will generate.

Other:

  * Centralize the `$(Company)` and `$(Copyright)` values.
  * Various whitespace changes due to `.editorconfig`.

[0]: https://github.com/devlooped/GitInfo
[1]: https://www.nuget.org/packages/GitInfo/2.1.2
[2]: https://github.com/xamarin/xamarin-android/commit/b620689ddf0214b1e38d5feab9e2ea7a653614ff