Use Dependabot

Closes gh-871

.github/workflows/dependabot.yml

@@ -0,0 +1,43 @@
+version: 2
+updates:
+  - package-ecosystem: gradle
+    target-branch: main
+    milestone: 77 # 3.2.x
+    directory: /
+    schedule:
+      interval: daily
+      time: '03:00'
+      timezone: Etc/UTC
+    labels:
+      - 'type: dependency-upgrade'
+      - 'in: build'
+    ignore:
+      - dependency-name: org.apache.directory.server:*
+      - dependency-name: org.junit:junit-bom
+        update-types:
+          - version-update:semver-major
+      - dependency-name: org.mockito:mockito-bom
+        update-types:
+          - version-update:semver-major
+      - dependency-name: '*'
+        update-types:
+          - version-update:semver-major
+          - version-update:semver-minor
+
+  - package-ecosystem: github-actions
+    target-branch: main
+    directory: /
+    schedule:
+      interval: weekly
+    labels:
+      - 'type: task'
+      - 'in: build'
+  - package-ecosystem: github-actions
+    target-branch: docs-build
+    directory: /
+    schedule:
+      interval: weekly
+    labels:
+      - 'type: task'
+      - 'in: build'
+