chore: add Dependabot configuration for automated dependency updates

Author: pubino

.github/dependabot.yml

@@ -0,0 +1,25 @@
+version: 2
+updates:
+  # GitHub Actions
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+      day: "monday"
+    commit-message:
+      prefix: "chore(deps)"
+    labels:
+      - "dependencies"
+      - "github-actions"
+
+  # Bundler (Ruby gems)
+  - package-ecosystem: "bundler"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+      day: "monday"
+    commit-message:
+      prefix: "chore(deps)"
+    labels:
+      - "dependencies"
+      - "ruby"