Keep Cabal caches fresher

[Anton-Latukha]

GitHub made a lazy version of the caching system - it essentially lays the hassle of keeping cache versions on the CI users. And probably it is a proper solution.

The default cache actions, and what people have - builds the cache one time and reuses the oldest builds cache for GHC, so everything on top keeps rebuilding.

Design and do the key-versioning system inside GitHub CI constraints that would allow to build, save and reuse new caches effectively.