fix(test): run cabal update prior to GitHub Action tests

This is due to haskell/cabal#8944

Previously, we were getting only a warning. It was fine as we are using
Nix to provision the packages.

Now (as of cabal-install v3.12.1.0), we are getting an error. To avoid
this, we need to run `cabal update` prior to running the tests.

Note that there are ongoing discussions on how to handle this going
forward.

Author: vst

.github/workflows/check.yaml

@@ -22,4 +22,4 @@ jobs:
 
       - name: "Check, Test and Build"
         run: |
-          nix-shell --pure --run "dev-test-build"
+          nix-shell --pure --run "cabal update --ignore-project && dev-test-build"