build: add autorelease-pending label

.github/workflows/release-please.yaml

@@ -66,6 +66,20 @@ jobs:
           fork: true
           package-name: ${{env.ACTION_NAME}}
           command: release-pr
+      - id: label
+        if: ${{ steps.release-pr.outputs.pr }}
+        uses: actions/github-script@v3
+        with:
+            github-token: ${{secrets.GITHUB_TOKEN}}
+            script: |
+              const [owner, repo] = process.env.GITHUB_REPOSITORY.split('/');
+              await github.issues.addLabels({
+                owner,
+                repo,
+                issue_number: ${{steps.release-pr.outputs.pr}},
+                labels: ['autorelease: pending']
+              });
+              console.log(`Tagged ${{steps.release-pr.outputs.pr}}`)
   release-please-release:
     runs-on: ubuntu-latest
     needs: [build]