Add update dependencies workflow

Author: peter-evans

.github/workflows/update-dep.yml

@@ -0,0 +1,31 @@
+name: Update Dependencies
+on:
+  schedule:
+    - cron:  '0 8 * * 6'
+jobs:
+  update-dep:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-java@v1
+        with:
+          java-version: 1.8
+      - name: Grant execute permission for gradlew
+        run: chmod +x gradlew
+      - name: Perform dependency resolution and write new lockfiles
+        run: ./gradlew dependencies --write-locks
+      - name: Create Pull Request
+        uses: peter-evans/create-pull-request@v2
+        with:
+            token: ${{ secrets.ACTIONS_BOT_TOKEN }}
+            commit-message: Update dependencies
+            committer: GitHub <noreply@github.com>
+            author: actions-bot <actions-bot@users.noreply.github.com>
+            title: Update dependencies
+            body: |
+              - Dependency updates
+  
+              Auto-generated by [create-pull-request][1]
+  
+              [1]: https://github.com/peter-evans/create-pull-request
+            branch: update-dependencies