update MonoMod.Core to 1.2.2 to address net9 issue

[stiefeljackal]

This PR address the issue with Harmony when running under .NET 9. As @tyb-dev pointed out, .NET 9 changed LocalBuilder from sealed partial class to abstract class. Due to this, MonoMod.Core on 1.2.1 was failing because it was attempting to create an instance of LocalBuilder, resulting in the following:

System.MemberAccessException : Cannot create an instance of System.Reflection.Emit.LocalBuilder because it is an abstract class.

MonoMod.Core was updated to 1.2.2 roughly six days ago to address this update to LocalBuilder. Updating the package reference to 1.2.2 addresses this issue with Harmony, and all tests are now passing. There was one test that required an update due to type checking for LocalBuilder (now RuntimeLocalBuilder when on .NET 9).

[pardeike]

Thanks, last time I checked it was not released