119467b3 

Add `cabal check` to Haskell flake

Get some assurance that Hackage will accept a published package.
Time to Start Worker time Duration Time to finish
Config 0s 1s 1s 1s
Eval 1s 4s 4s 6s
Build 6s 1m59s 2m01s 2m08s
Suite 0s 2m05s 2m07s 2m08s