.NET 8 Debian images should be based on Bookworm

[richlander]

We expect that Debian Bookworm will ship before .NET 8. We did this same race with .NET 6 and Debian Bullseye. Fortunately, .NET 6 lost that race and we expect that .NET 8 will similarly lose the race with Bookworm.

For .NET 6, we shipped Bullseye images starting with .NET 6 Preview 1. We should use the same model here.

• https://www.debian.org/releases/bookworm/
• https://wiki.debian.org/DebianBookworm
• https://devblogs.microsoft.com/dotnet/announcing-net-6/#debian-11-bullseye

[richlander]

We need to decide on broad test coverage for Bookworm. Do we need a new test leg for this on dotnet/runtime (for example)?

@mmitche @ViktorHofer

[ViktorHofer]

In dotnet/runtime we currently test both Debian 10 and 11. Based on https://wiki.debian.org/DebianReleases, Debian 10 already reached EOL. Would it make sense to remove 10 and add 12?

[ViktorHofer]

cc @wfurt @ericstj @carlossanlop

[mthalman]

[Triage]
We should target .NET 8 Preview 1 to get the Debian Dockerfiles updated to be on Bookworm.