feat: add dependabot with auto merge workflow

.github/dependabot.yml

@@ -0,0 +1,13 @@
+version: 2
+updates:
+  # Maintain dependencies for GitHub Actions
+  - package-ecosystem: 'github-actions'
+    directory: '/'
+    schedule:
+      interval: 'weekly'
+
+  # Maintain dependencies for npm
+  - package-ecosystem: 'npm'
+    directory: '/'
+    schedule:
+      interval: 'weekly'

.github/workflows/dependabot.auto.yml

@@ -0,0 +1,27 @@
+name: 'Dependabot Automerge - Action'
+
+on:
+  pull_request:
+
+jobs:
+  worker:
+    runs-on: ubuntu-latest
+
+    if: github.actor == 'dependabot[bot]'
+    steps:
+      - name: automerge
+        uses: actions/github-script@0.2.0
+        with:
+          script: |
+            github.pullRequests.createReview({
+              owner: context.payload.repository.owner.login,
+              repo: context.payload.repository.name,
+              pull_number: context.payload.pull_request.number,
+              event: 'APPROVE'
+            })
+            github.pullRequests.merge({
+              owner: context.payload.repository.owner.login,
+              repo: context.payload.repository.name,
+              pull_number: context.payload.pull_request.number
+            })
+          github-token: ${{github.token}}