added own cache to substituters.

.forgejo/workflows/check.yaml

@@ -11,4 +11,8 @@ jobs:
         uses: https://git.collective-conciousness.monster/Ittihadyya/nix-actions/install@main
         with:
           install-url: "https://nixos.org/nix/install"
-      - run: nix fmt $(find ./ -regex '.*.nix$') -- --check
+      - name: Check file formatting
+        run: |
+          echo "extra-substituters = https://cache.collective-conciousness.monster" >> /etc/nix/nix.conf
+          echo "extra-trusted-public-keys = adyya-flake:PAbC0hnAiNj/kHcm9wIykmKIf25FDeXB6JusqlX2ghs=" >> /etc/nix/nix.conf
+          nix fmt $(find ./ -regex '.*.nix$') -- --check