[CI] Use custom github action for backport (#91523)

.github/workflows/backport.yml

@@ -18,34 +18,20 @@ jobs:
       )
     runs-on: ubuntu-latest
     steps:
-      - name: 'Get backport config'
-        run: |
-          curl 'https://raw.githubusercontent.com/elastic/kibana/master/.backportrc.json' > .backportrc.json
-
-      - name: Use Node.js 14.x
-        uses: actions/setup-node@v1
+      - name: Checkout Actions
+        uses: actions/checkout@v2
         with:
-          node-version: 14.x
+          repository: 'elastic/kibana-github-actions'
+          ref: main
+          path: ./actions
 
-      - name: Install backport CLI
-        run: npm install -g backport@5.6.4
+      - name: Install Actions
+        run: npm install --production --prefix ./actions
 
-      - name: Backport PR
-        run: |
-          git config --global user.name "kibanamachine"
-          git config --global user.email "42973632+kibanamachine@users.noreply.github.com"
-          backport --fork true --username kibanamachine --accessToken "${{ secrets.KIBANAMACHINE_TOKEN }}" --ci --pr "$PR_NUMBER" --labels backport --assignee "$PR_OWNER" | tee 'output.log'
-        env:
-          PR_NUMBER: ${{ github.event.pull_request.number }}
-          PR_OWNER: ${{ github.event.pull_request.user.login }}
-
-      - name: Report backport status
-        run: |
-          COMMENT="Backport result
-          \`\`\`
-          $(cat output.log)
-          \`\`\`"
-
-          GITHUB_TOKEN="${{ secrets.KIBANAMACHINE_TOKEN }}" gh api -X POST repos/elastic/kibana/issues/$PR_NUMBER/comments -F body="$COMMENT"
-        env:
-          PR_NUMBER: ${{ github.event.pull_request.number }}
+      - name: Run Backport
+        uses: ./actions/backport
+        with:
+          branch: master
+          github_token: ${{secrets.KIBANAMACHINE_TOKEN}}
+          commit_user: kibanamachine
+          commit_email: 42973632+kibanamachine@users.noreply.github.com