correct github action

Author: peterbecich

.github/workflows/nix-flake.yml

@@ -9,6 +9,10 @@ jobs:
       - uses: actions/checkout@v4
 
       - uses: nixbuild/nix-quick-install-action@v30
+        with:
+          nix_conf: |
+            keep-env-derivations = true
+            keep-outputs = true
 
       - name: Restore and save Nix store
         uses: nix-community/cache-nix-action@v6