chore: add Cloudflare Pages deploy workflow for fork previews

Author: paulacianelli

.github/workflows/deploy.yml

@@ -1,4 +1,7 @@
-on: [push]
+on:
+  push:
+  pull_request_target:
+    types: [opened, synchronize, reopened]
 
 jobs:
   deploy:
@@ -7,12 +10,15 @@ jobs:
     permissions:
       contents: read
       deployments: write
+      pull-requests: write
 
     name: Deploy to Cloudflare Pages
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
 
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1
@@ -25,11 +31,27 @@ jobs:
           JEKYLL_ENV: production
 
       - name: Publish
+        id: cloudflare
         uses: cloudflare/pages-action@v1.5.0
         with:
           apiToken: ${{ secrets.CLOUDFLARE_API_TOKEN }}
           accountId: ${{ secrets.CLOUDFLARE_ACCOUNT_ID }}
           projectName: ruby-uy
           directory: _site
-          gitHubToken: ${{ secrets.GITHUB_TOKEN }}
           wranglerVersion: '3'
+          branch: ${{ github.event.pull_request.head.ref || github.ref_name }}
+
+      - name: Comment preview URL on PR
+        if: github.event_name == 'pull_request_target'
+        uses: actions/github-script@v7
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          script: |
+            github.rest.issues.createComment({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: `🔍 Preview: ${process.env.DEPLOY_URL}`
+            })
+        env:
+          DEPLOY_URL: ${{ steps.cloudflare.outputs.url }}