update approve_and_merge.yml (#388)

Author: ktr0731

.github/workflows/approve_and_merge.yml

@@ -1,25 +1,33 @@
-name: "Auto approve and merge Pull Requests"
+name: "Auto approve Pull Requests and enable auto-merge"
 on:
   pull_request_target
 jobs:
   worker:
     runs-on: ubuntu-latest
     if: github.actor == 'dependabot[bot]'
     steps:
-      - name: Auto approve and merge Pull Request
+      - name: automerge
         uses: actions/[email protected]
         with:
-          github-token: "${{ secrets.GITHUB_TOKEN }}"
+          github-token: "${{ secrets.GH_TOKEN }}"
           script: |
             await github.pulls.createReview({
               owner: context.repo.owner,
               repo: context.repo.repo,
               pull_number: context.issue.number,
-              event: "APPROVE"
-            })
-            await github.pulls.merge({
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              pull_number: context.issue.number,
-              merge_method: "squash"
+              event: 'APPROVE'
             })
+
+            const res = await github.graphql(`query {
+              repository(owner: "${context.repo.owner}", name: "${context.repo.repo}") {
+                pullRequest(number: ${context.issue.number}) {
+                  id
+                }
+              }
+            }`)
+
+            await github.graphql(`mutation {
+              enablePullRequestAutoMerge(input: { pullRequestId: "${res.repository.pullRequest.id}" }) {
+                clientMutationId
+              }
+            }`)