Dependabot configuration to update actions in workflows

.github/dependabot.yml

@@ -1,7 +1,14 @@
 version: 2
 updates:
-  # Only check for Ruby gem updates
+  # Check for Ruby gem updates
   - package-ecosystem: "bundler"
     directory: "/"
     schedule:
       interval: "daily"
+  # Check for GitHub Actions updates
+  - package-ecosystem: "github-actions"
+    # Look for GitHub Actions workflows in the `root` directory
+    directory: "/"
+    # Check the for updates once a week
+    schedule:
+      interval: "weekly"