Warn when installed GHC and HLS versions are not compatible

I would like to be notified when using ghcup if the installed HLS and GHC versions are not compatible. For example, if I currently (as of today) install GHC and HLS from scratch, I get GHC 8.10.7 and HLS 1.3.0, which doesn't work with that GHC version. I'd like to see a warning before doing this, and be offered the chance to install GHC 8.10.5 instead.

How should ghcup determine which HLS versions are compatible with which GHC versions? Good question, but the same issue comes up in https://github.com/haskell/vscode-haskell/issues/454, so maybe there could be some support for HLS publishing this information with each release in a human readable format that ghcup (and the VSCode extension, as well) could consume.