.NET 7 TODO list

[jonpryor]

When xamarin/java.interop/main begins targeting .NET 7, the following must be done:

• Update GitInfo.txt to have value 7.0: https://github.com/xamarin/java.interop/blob/eb52a5cb3bd9cbb06ba7b72186080ab711826328/GitInfo.txt#L1
• Revert [Java.Interop] net6.0 is Version=v0.1.0.0 #961, so that $(_NetCoreLibVersion) is once again $(GitBaseVersionMajor).$(GitBaseVersionMinor).0.0. This will ensure that Java.Interop.dll/etc. will have a version number of 7.0 instead of 0.1.0.0.