ci: Install only the required nix tools

A previous commit allowed to select each tool separately on the toolbox.

This commit makes use of that for CI to possibly speed up loading from cachix
a little bit. It will also cause fewer cache misses when nix code is changed.

Resolves #3183

.github/workflows/check.yaml

@@ -25,7 +25,7 @@ jobs:
         uses: ./.github/actions/setup-nix
         with:
           authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
-          tools: style
+          tools: style.lint.bin style.styleCheck.bin
       - name: Run linter (check locally with `nix-shell --run postgrest-lint`)
         run: postgrest-lint
       - name: Run style check (auto-format with `nix-shell --run postgrest-style`)