Bump Roslyn to 4.13

[sailro]

Bump Roslyn to 4.13

Checklist

• I have read the Contribution Guide ;

[AlfishSoftware]

This has made it stop working in my library build on the latest Ubuntu 25.04, where the latest .NET 9 version available when installed by apt is currently 9.0.108. I got this warning:

CSC : warning CS9057: The analyzer assembly '/home/.../.nuget/packages/microsoft.unity.analyzers/1.23.0/analyzers/dotnet/cs/Microsoft.Unity.Analyzers.dll' references version '4.14.0.0' of the compiler, which is newer than the currently running version '4.12.0.0'.

I had to pin the dependency to 1.22.* to fix it:

<PackageReference Include="Microsoft.Unity.Analyzers" Version="1.22.*" PrivateAssets="All" />

Which is unfortunate, as it now requires me to know when I'll be able to unpin it and to remember to do it.

[AlfishSoftware]

Perhaps it would be appropriate to bump major version when minimum .NET requirements to use the lib change? Like from net8 to net9? And maybe to avoid moving further than whatever is the latest available .NET on Ubuntu (which is a Linux distro officially supported by Unity)?

[sailro]

Indeed, thank you for your message. I'm going to have a look.

Previously we had distinct dependencies for the analyzer (3.x) and the test project (4.x), but this caused issues with dependabot. We unified those dependencies recently and I think that's why.

No impact when shipping in IDEs, but indeed you can hit a regression when directly using the nuget.

I'm going to see how we can revert that.