Update test matrix for .net 8

[wtgodbe]

Update the OS's we test on for .Net 8 - Will involve updating the helix images defined in https://github.com/dotnet/aspnetcore/blob/main/eng/targets/Helix.Common.props

Proposal:

• Update Alpine 3.14 -> 3.15 (EOL 11/23) or 3.16 (EOL 05/24)
• Update Fedora 34 -> 36
• Consider updating Ubuntu 20.04 -> 22.04

[ghost]

Thanks for contacting us.

We're moving this issue to the .NET 8 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.