ci: cache Nix store with cache-nix-action #2161

Job	Run time
Build Linux (Cabal, GHC 9.0.2)	22m 59s
Build MacOS (Nix)	10m 6s
Build Linux (Cabal, GHC 9.2.4)	29m 8s
Build Linux (Stack)	3m 21s
Build aarch64 (Cabal, GHC ${{ matrix.ghc }})	0s
Build MacOS (Stack)	5m 30s
Get FreeBSD build from CirrusCI	5m 18s
Build Windows (Stack)	6m 10s
Build Linux static (Nix)	2m 15s
Lint & check code style	2m 14s
Test memory (Nix)	2m 43s
Test (Nix)	7m 41s
Test PG 9.6 (Nix)	6m 18s
Test PG 10 (Nix)	6m 4s
Test PG 11 (Nix)	6m 3s
Test PG 12 (Nix)	6m 55s
Test PG 13 (Nix)	6m 1s
Test PG 14 (Nix)	7m 3s
Test PG 15 (Nix)	7m 37s
Test PG 16 (Nix)	6m 19s
Prepare release	0s
Release on Docker Hub	0s
Release on GitHub	0s
Release Arm Builds on Docker Hub	0s
Remove copied files from server	0s
	2h 29m 45s

Provide feedback