Add GitHub Actions build workflow and migrate DecodeTest to .NET 10.0

[Copilot]

• Add build pipeline that runs on every PR to main.
• Migrate .NET Core 3.1 projects to multi-target .NET 6.0, .NET 8.0, and .NET 10.0.
  • Why? Just in case somebody has a .NET 6.0 project that is using the nuget package. This should not be a breaking change for them.
    • This is only really relevant to the Provider dll, which doesn't target netstandard21 because it wants to use some functionality that is only available in 5.0+.
  • I don't know if there are any advantages to including the 8 and 10 versions in the nuget package, since the code is identical, but there does seem to be some difference between the 6.0 and 8.0 dlls (but not between the 8.0 and 10.0 dlls?).
• dotnet test support is highly improved in .NET 10, so build using the 10 SDK
• Suppress warnings that appear when compiling with .NET 10.0, because the fixes are incompatible when building for 6.0.

[Robo210]

@copilot retarget the .netcore 3.1 projects to .net 8

[Copilot]

@copilot retarget the .netcore 3.1 projects to .net 8

Retargeted DecodeTest project to net8.0 in commit 494a2cd. Updated MSTest packages to version 3.6.3, fixed deprecated TestContext API usage, and added workarounds for MSTest/VSTest dependency resolution with .NET 8.0.

[Robo210]

@idigdoug if this is targeting net6, and this is the "main" library for using tracepoints, what is the point of having the other libraries target netstandard21? They aren't super useful on their own, and nobody is going to use, e.g., the Types library in a .net core 3.1 app because that went out of support years before this was written.

[Robo210]

I think if we standardize on net6.0 as the lowest version to support in the nuget packages, nobody will be impacted. And once we want to make a bigger version number bump, we could drop net6 (already EOL for many years) for net8 (which itself will be EOL this year).

I'm not proposing to drop netstandard21 in this PR, but I think a subsequent one could safely do it.

[Robo210]

(yes, I know the Types dll doesn't have any meaningful code in it and could work with truly ancient .net versions, but building it for netstandard21 seems like an academic exercise and not practically useful in 2026)

[idigdoug]

Not sure how important it is, but the decoding support works with netstandard, and decoding is used by things like WPA. I don't remember what WPA targets.

[Robo210]

For some reason nuget was unhappy with the prior syntax for this package (the rest were fine). I couldn't make it happy, so I just switched to this alternative syntax and now everything works.