Added Dependabot config

.github/dependabot.yml

+version: 2
+updates:
+
+  # Maintain dependencies for GitHub Actions
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+
+  # Maintain dependencies for Docker
+  - package-ecosystem: "docker"
+    directory: "/"
+    schedule:
+      interval: "weekly"