chore: enable dependabot for java (risingwavelabs#19212)

.github/dependabot.yml

@@ -39,10 +39,29 @@ updates:
     google-cloud:
       patterns:
         - "google-cloud*"
+
 # Don't update these directories
 - package-ecosystem: cargo
   directory: /integration_tests/feature-store
   schedule:
     interval: "daily"
   ignore:
     - dependency-name: "*"
+
+- package-ecosystem: maven
+  directory: /java
+  schedule:
+    interval: "weekly"
+  open-pull-requests-limit: 5
+  # Disable auto rebase to reduce cost. Use `@dependabot rebase` manually instead.
+  rebase-strategy: "disabled"
+  ignore:
+    # Do not bump Debezium because we have hacked its source code e.g. #18760
+    - dependency-name: "io.debezium:*"
+      update-types:
+        ["version-update:semver-minor", "version-update:semver-major"]
+  groups:
+    # Group all dependenies together because Java libraries are quite stable
+    all:
+      patterns:
+        - "*"