added review-trigger (#7)

Copied from paritytech/polkadot-sdk#3431

.github/workflows/review-trigger.yml

@@ -0,0 +1,68 @@
+name: Review-Trigger
+
+on:
+  pull_request_target:
+    types:
+      - opened
+      - reopened
+      - synchronize
+      - review_requested
+      - review_request_removed
+      - ready_for_review
+  pull_request_review:
+
+jobs:
+  trigger-review-bot:
+    # (It is not a draft) && (it is not a review || it is an approving review)
+    if: ${{ github.event.pull_request.draft != true && (github.event_name != 'pull_request_review' || (github.event.review && github.event.review.state == 'APPROVED')) }}
+    runs-on: ubuntu-latest
+    name: trigger review bot
+    steps:
+      - name: Skip merge queue
+        if: ${{ contains(github.ref, 'gh-readonly-queue') }}
+        run: exit 0
+      - name: Get comments
+        id: comments
+        run: echo "bodies=$(gh pr view ${{ github.event.number }} --repo ${{ github.repository }} --json comments --jq '[.comments[].body]')" >> "$GITHUB_OUTPUT"
+        env:
+          GH_TOKEN: ${{ github.token }}
+      - name: Fail when author pushes new code
+        # Require new reviews when the author is pushing and he is not a member
+        if: |
+          github.event_name == 'pull_request_target' &&
+          github.event.action == 'synchronize' && 
+          github.event.sender.login == github.event.pull_request.user.login && 
+          github.event.pull_request.author_association != 'MEMBER'
+        run: |
+          # We get the list of reviewers who approved the PR
+          REVIEWERS=$(gh api repos/${{ github.repository }}/pulls/${{ github.event.number }}/reviews \
+          --jq '{reviewers: [.[] | select(.state == "APPROVED") | .user.login]}')
+
+          # We request them to review again
+          echo $REVIEWERS | gh api --method POST repos/${{ github.repository }}/pulls/${{ github.event.number }}/requested_reviewers --input -
+          
+          echo "::error::Project needs to be reviewed again"
+          exit 1
+        env:
+          GH_TOKEN: ${{ github.token }}
+      - name: Comment requirements
+        # If the previous step failed and github-actions hasn't commented yet we comment instructions
+        if: failure() && !contains(fromJson(steps.comments.outputs.bodies), 'Review required!')
+        run: |          
+          gh pr comment ${{ github.event.number }} --repo ${{ github.repository }} --body "Review required! Latest push from author must always be reviewed"
+        env:
+          GH_TOKEN: ${{ github.token }}
+          COMMENTS: ${{ steps.comments.outputs.users }}
+      - name: Get PR number
+        env:
+          PR_NUMBER: ${{ github.event.pull_request.number }}
+        run: |
+          echo "Saving PR number: $PR_NUMBER"
+          mkdir -p ./pr
+          echo $PR_NUMBER > ./pr/pr_number
+      - uses: actions/upload-artifact@v3
+        name: Save PR number
+        with:
+          name: pr_number
+          path: pr/
+          retention-days: 5