ci: add maven and docker to dependabot configuration

.github/dependabot.yml

@@ -1,7 +1,15 @@
 version: 2
 updates:
-  # Maintain dependencies for GitHub Actions
     -   package-ecosystem: "github-actions"
         directory: "/"
         schedule:
-      interval: "daily"
+            interval: "weekly"
+    -   package-ecosystem: "maven"
+        directory: "/"
+        schedule:
+            interval: "weekly"
+    -   package-ecosystem: "docker"
+        directory: "/"
+        schedule:
+            interval: "weekly"
+