Run nix-fast-build from the GH Actions workflow

No need to run an extra shell script to run nix-fast-build.

Author: jfroche

.github/workflows/nix-build.yml

@@ -70,8 +70,10 @@ jobs:
             substituters = https://cache.nixos.org https://nix-postgres-artifacts.s3.amazonaws.com
             trusted-public-keys = nix-postgres-artifacts:dGZlQOvKcNEjvT7QEAJbcV6b6uk7VF/hWMjhYleiaLI=% cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=
       - name: Build psql bundle
-        run: |
-          ./docker/nix/build_nix.sh
+        run: >
+            nix run "github:Mic92/nix-fast-build?rev=b1dae483ab7d4139a6297e02b6de9e5d30e43d48" 
+            -- --skip-cached --no-nom 
+            --flake ".#checks.$(nix eval --raw --impure --expr 'builtins.currentSystem')"
         env:
           AWS_ACCESS_KEY_ID: ${{ env.AWS_ACCESS_KEY_ID }}
           AWS_SECRET_ACCESS_KEY: ${{ env.AWS_SECRET_ACCESS_KEY }}