Prepare for NET 9 SDK analysis

[lahma]

NET 9 SDK has more rules and will cause build problems. Creating a TODO list for focused PRs in Directory.Build.props via NoWarn items, fixing small easy wins inside the PR. Now compiles with NET 9 SDK. All changes made with IDE automation.

[RicoSuter]

@lahma can you maybe also add a fix for this windows CI build failure (conflict)?

https://github.com/RicoSuter/NJsonSchema/actions

[lahma]

Sure, gimme an hour so that I get back to computer, I've dealt with this before.

[lahma]

@RicoSuter should now publish only on Windows (this changed with v4 actions and they will error if multiple jobs try to do it), also brought back merge-conflicted analysis fixes.

[RicoSuter]

Thanks for the fix, can we merge this PR then?
Is this necessary for new NSwag release or can this also wait?

[lahma]

Can be merged. This is not needed for NSwag, but if you want to compile with NET 9 SDK (global.json now only allows 8.0) there would be compile errors, after this, no more. I can create a separate PR to switch to NET 9 SDK or add is as part of this too.

[RicoSuter]

Can be merged. This is not needed for NSwag, but if you want to compile with NET 9 SDK (global.json now only allows 8.0) there would be compile errors, after this, no more. I can create a separate PR to switch to NET 9 SDK or add is as part of this too.

Yes please update PR to use .NET 9 then...
So the changes are "cosmetic" only right?

[lahma]

Can be merged. This is not needed for NSwag, but if you want to compile with NET 9 SDK (global.json now only allows 8.0) there would be compile errors, after this, no more. I can create a separate PR to switch to NET 9 SDK or add is as part of this too.

Yes please update PR to use .NET 9 then... So the changes are "cosmetic" only right?

Changes are cosmetic, done with IDE auto fixes (Rirder, but I believe these are Roslyn based).

[lahma]

@RicoSuter now uses (and requires) NET 9 SDK when building.