Fix ci update hackage index

[jneira]

• Fix freeze cache key correctly #2560 fixed the cabal freeze step putting cabal update before it
• But it had a unintended effect detected in the ghc-9.2 branch: the hackage index bump done by cabal update was being overwritten by the package sources cache restoring done immediately after
• Also reviewing ci logs i also checked the freeze file hash was not being computed. It seems the ${{ hasFiles('...') }} is resolved before the script is run 🤦

[Anton-Latukha]

[skip circleci]

[Anton-Latukha]

Please, consider hackage.yml comment before merging.

[Anton-Latukha]

It is also good that hackage store cache does not depend on the freeze file, so we can do this (load the source cache before determining the general cache key).

[Anton-Latukha]

Yes. It is seen in https://github.com/haskell/haskell-language-server/runs/4701985268?check_suite_focus=true that echo ::set-output name=value::${{ hashFiles('cabal.project.freeze') }} was not producing the hash:

Cache hit occurred on the primary key compiled-deps-macOS-8.10.6-2021-12-29T12-30-08Z-, not saving cache.

[Anton-Latukha]

Nice.

[Anton-Latukha]

Seems to work in ghc-9.2: https://github.com/haskell/haskell-language-server/runs/4703678203?check_suite_focus=true.