CI: Caching seems not to do anything

[fendor]

CI runs are incredibly slow and seem to have no caching whatsoever:

What's going on? At least dependencies should always be cached.

[andys8]

Haven't looked into it, but want to share that there is a quite newish page that shows caching details for GitHub.

https://github.com/haskell/haskell-language-server/actions/caches

Also this subpage contains this warning - which might or might not be relevant for this issue.

[fendor]

-_- Cant we just buy more cache? Or we have to be smarter when it comes to artefact sharing.

[hasufell]

10GB is nowhere near enough.

We should use cabal-cache: https://hackage.haskell.org/package/cabal-cache

I'm currently trying to implemented it for ghcup CI as well. Is uses S3 and supports multicloud. We can just buy backblaze bucket with the opencollective money.