Refactor patch action to use create-pull-request action (#2186)

.github/workflows/serverless-patch.sh

@@ -15,31 +15,25 @@ cd "$GITHUB_WORKSPACE/serverless"
 git checkout -b "apply-patch-$pull_request_id"
 git am -C1 --reject /tmp/patch.diff || git am --quit
 
-# commit changes, ignoring rejects
-git add -A
-git reset -- **/*.rej
-git commit -m "Apply changes from $pr_shortcode"
-
+# generate PR body comment
 comment="Patch applied from $pr_shortcode"
 
 # enumerate rejected patches in PR comment
-tick='\`' # just trying to satisfy shellcheck here
-has_rejects=''
+has_rejects='false'
 for f in ./**/*.rej; do
-  has_rejects='--draft'
+  has_rejects='true'
   comment="$comment
 
-## Rejected patch $tick$f$tick must be resolved:
+## Rejected patch \`$f\` must be resolved:
 
-$tick$tick$tick
+\`\`\`diff
 $(cat "$f")
-$tick$tick$tick
+\`\`\`
 "
 done
 
-# open a PR
-gh pr create \
-  --repo elastic/elasticsearch-serverless-js \
-  -t "Apply PR changes from $pr_shortcode" \
-  --body "$comment" \
-  "$has_rejects"
+# send data to output parameters
+{
+  echo "PR_BODY='$comment'"
+  echo "PR_DRAFT=$has_rejects"
+} >> "$GITHUB_OUTPUT"

.github/workflows/serverless-patch.yml

@@ -37,11 +37,16 @@ jobs:
           repository: elastic/elasticsearch-serverless-js
           ref: main
           path: serverless
-      - name: Set Git user
-        run: |
-          git config --global user.name "Elastic Machine"
-          git config --global user.email "elasticmachine@users.noreply.github.com"
       - name: Apply patch from stack to serverless
-        env:
-          GH_TOKEN: '${{ secrets.GITHUB_TOKEN }}'
+        id: apply-patch
         run: $GITHUB_WORKSPACE/stack/.github/workflows/serverless-patch.sh
+      - uses: peter-evans/create-pull-request@v6
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          path: $GITHUB_WORKSPACE/serverless
+          title: 'Apply patch from elastic/elasticsearch-js#${{ github.event.pull_request.number }}'
+          commit-message: 'Apply patch from elastic/elasticsearch-js#${{ github.event.pull_request.number }}'
+          branch-suffix: short-commit-hash
+          body: '${{ steps.apply-patch.outputs.PR_BODY }}'
+          draft: '${{ steps.apply-patch.outputs.PR_DRAFT }}'
+          add-paths: ':!*.rej'