remove attic push

.github/workflows/flake-update.yml

@@ -16,6 +16,13 @@ jobs:
               uses: sigyl-actions/gitea-action-get-latest-release@main
               with:
                 repository: ahuston-0/determinate-nix-installer
+            - name: Setup Attic cache
+              uses: ryanccn/attic-action@v0
+              with:
+                endpoint: ${{ secrets.ATTIC_ENDPOINT }}
+                cache: ${{ secrets.ATTIC_CACHE }}
+                token: ${{ secrets.ATTIC_TOKEN }}
+                skip-push: "true"
             - name: Install nix
               uses: https://github.com/DeterminateSystems/nix-installer-action@main
               with: