enable dependabot on firebase functions

.github/dependabot.yml

@@ -10,6 +10,12 @@ updates:
     schedule:
       interval: "weekly"
 
+  # Also check deps on the firebase functions
+  - package-ecosystem: "pnpm" # See documentation for possible values
+    directory: "/functions" # Location of package manifests
+    schedule:
+      interval: "weekly"
+
   - package-ecosystem: "github-actions"
     # Workflow files stored in the default location of `.github/workflows`. (You don't need to specify `/.github/workflows` for `directory`. You can use `directory: "/"`.)
     directory: "/"