add dependabot config for npm dependencies

for dependabot config docs -> please also see: https://docs.github.com/en/code-security/supply-chain-security/keeping-your-dependencies-updated-automatically/configuration-options-for-dependency-updates#package-ecosystem

.github/dependabot.yml

@@ -2,6 +2,12 @@ version: 2
 updates:
   # Maintain dependencies for GitHub Actions
   - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"
+
+    # Maintain dependencies for npm
+  - package-ecosystem: "npm"
     directory: "/"
     schedule:
       interval: "daily"