[enhancement]: UseDotNet should support `major.minor.patchXX' syntax to support floating within an SDK feature band

[baronfel]

Task name

UseDotNet@2

Describe your feature request here

It's a common need to use a version of the .NET SDK that matches your VS install (as described by the https://aka.ms/dotnet/matrixofpaine) but to still remain on the latest patch release within that feature band.

The actions/setup-dotnet action for GitHub workflows supports specifying a version like 8.0.3xx to opt into 'latest patch release in the 300 feature band' semantics, and I think AzDo users should be able to use such a syntax as well.

[aleksandrlevochkin]

Hi @baronfel, thanks for your proposal! We are currently working on higher-prioritized issues, but will get back to this one as soon as we can

[NickCraver]

@aleksandrlevochkin For what it's worth, this is affecting our ability to stay up to date with CG compliance, as our choices are "ping not to break, having to update all old branches" or "don't pin, and break whenever SDK vs. VS-in-image" is incompatible" (which took our all of our builds globally last Tuesday.

If I can help provide justification here, ping away on Teams.