ci: number-rfc creates a PR instead of pushing to main

Branch protection requires PRs and status checks. The workflow now
creates a short-lived branch, opens a PR, and enables auto-merge so
it lands once CI passes.

Author: filvecchiato

.github/workflows/number-rfc.yml

@@ -8,6 +8,7 @@ on:
 
 permissions:
   contents: write
+  pull-requests: write
 
 jobs:
   number-rfc:
@@ -106,14 +107,24 @@ jobs:
 
           mv _index.md.tmp _index.md
 
-      - name: Commit and push
+      - name: Create PR if changes exist
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: |
           git config user.name "github-actions[bot]"
           git config user.email "github-actions[bot]@users.noreply.github.com"
           if git diff --cached --quiet && git diff --quiet; then
             echo "Nothing to commit."
             exit 0
           fi
+          BRANCH="ci/update-rfc-index-$(date +%s)"
+          git checkout -b "$BRANCH"
           git add docs/rfcs/
           git commit -m "Update RFC index"
-          git push
+          git push origin "$BRANCH"
+          gh pr create \
+            --title "ci: update RFC index" \
+            --body "Auto-generated by the number-rfc workflow." \
+            --head "$BRANCH" \
+            --base main
+          gh pr merge "$BRANCH" --auto --squash