chore(ci): add workflow to suggest splitting large PRs

.github/scripts/comment_on_large_pr.js

@@ -0,0 +1,25 @@
+const {
+  PR_NUMBER,
+  IGNORE_AUTHORS,
+} = require("./constants")
+
+module.exports = async ({github, context, core}) => {
+    if (IGNORE_AUTHORS.includes(PR_AUTHOR)) {
+      return core.notice("Author in IGNORE_AUTHORS list; skipping...")
+    }
+
+    core.info(`Commenting on PR ${PR_NUMBER}`)
+
+    let msg = `
+    ### ⚠️Large PR detected⚠️.
+
+    Please consider breaking into smaller PRs to avoid significant review delays. Ignore if this PR has naturally grown to this size after reviews.
+    `;
+
+    await github.rest.issues.createComment({
+      owner: context.repo.owner,
+      repo: context.repo.repo,
+      body: msg,
+      issue_number: PR_NUMBER,
+    });
+}

.github/workflows/on_label_added.yml

@@ -0,0 +1,25 @@
+name: On Label added
+
+on:
+  pull_request:
+    types:
+      - labeled
+
+jobs:
+  split-large-pr:
+    if: github.event.label.name == 'size/XXL'
+    runs-on: ubuntu-latest
+    permissions:
+      issues: write
+      pull-requests: write
+    steps:
+      - uses: actions/checkout@v3
+      - name: "Suggest split large Pull Request"
+        uses: actions/github-script@v6
+        env:
+          PR_NUMBER: ${{ github.event.issue.number }}
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          script: |
+            const script = require('.github/scripts/comment_on_large_pr.js')
+            await script({github, context, core})