Add support for Alpine 3.15

[rbhanda]

This issue is created to track progress for the work to enable Alpine 3.15 support for .NET core 3.1, .NET 5.0 and .NET 6.0

Product and Test updates

• [All teams] Do a compatibility check for the product with the new OS
• [CoreCLR/CoreFX] Runtime / RID Support update @wfurt
• [Infra] Ensure that the correct Docker images used by teams are built in the dotnet-buildtools-prereqs (if applicable)
• [Infra] Replace docker tags used in builds across repos and branches
• [CLI team] Update CI legs to latest updated Dockerfile
• [All teams] Update test infrastructure to support the new version
• [Acquisition] Add support within nightly repos
• [Acquisition] Deploy to master (GA) during next patch release cycle

Release team:

• Notify .NET Core teams regarding new OS release
• Update the supported OS content on GitHub and marketing sites.

Document updates:

• Add OS prerequisites to the dependencies document
• Update distro install page

[mthalman]

@wfurt - Can RID support be checked off? I see there were some PRs for this. Is it all done for all the supported .NET versions?

[mthalman]

There is an existing issue for PowerShell on Alpine 3.15 that will block full support for the official .NET container images: PowerShell/PowerShell#16532.

[mthalman]

@balachir, @richaverma1 - Has there been any test pass on top of Alpine 3.15? If not, can we get that done to get sign off on this?

[richaverma1]

@mthalman Alpine 3.15 was covered in .NET December update validation. There were no issues reported.

[wfurt]

it seems like dotnet/runtime#62938 was never ported back to 6.x (or other release branches)

[mthalman]

Is there time to get that in for Feb?

[rbhanda]

Tagging @mmitche since he can answer, but I doubt we have time to port this to 6.0 for Feb now

[mmitche]

No, we're behind on 6.0 at this point.

[mthalman]

@wfurt - You've identified this wasn't ported. Can we make that happen?

[wfurt]

dotnet/runtime#64304 pending for 6.0 and dotnet/corefx#43129 for 3.1