Bump GHC 9.0

Merge master into ghc-9.0.

changed target branch from master to ghc-9.0

added 2 commits

• 4fb53a39 - gitlab-ci: Only allow builders on "docker" runners
• 0b324ab6 - Freeze Hackage index state when building Haskell tools

Compare with previous version

merged

@maerwald, this commit is actually breaking. Specifically, we must cabal update at least twice: once as root to build the bootstrap tools and again as the ghc user (which will be used by downstream GHC builds).