Update dependabot.yml to also check maven dependencies

Author: drpy

.github/dependabot.yml

@@ -1,6 +1,13 @@
 version: 2
 updates:
+  # Maintain dependencies for GitHub Actions
   - package-ecosystem: "github-actions"
     directory: "/"
     schedule:
       interval: "weekly"
+  
+  # Maintain dependencies for Maven
+  - package-ecosystem: "maven"
+    directory: "/"
+    schedule:
+      interval: "weekly"