ci: Preview docs for PRs

.github/workflows/ci.yml

@@ -249,8 +249,28 @@ jobs:
 
       - name: Build docs
         run: target/debug/xtask doc --deny-warnings
+      
+      - name: Deploy PR preview
+        if: ${{ github.event_name == 'pull_request' }}
+        uses: dswistowski/surge-sh-action@v1.0.1
+        with:
+          domain: pr-${{ github.event.number }}--ruma-docs.surge.sh
+          project: target/doc
+          login: ${{ secrets.SURGE_LOGIN }}
+          token: ${{ secrets.SURGE_TOKEN }}
+      
+      - name: Comment deploy PR preview URL
+        if: ${{ github.event_name == 'pull_request' }}
+        uses: Beakyn/gha-comment-pull-request@v1.0.2
+        id: deploy-preview
+        env:
+          GITHUB_TOKEN: ${{ github.token }}
+        with:
+          description-message: |
+            ----
+            Preview: https://pr-${{ github.event.number }}--ruma-docs.surge.sh
 
-      - name: Deploy to docs branch
+      - name: Deploy to docs repo
         if: ${{ github.event_name == 'push' && github.ref == 'refs/heads/main' }}
         uses: JamesIves/github-pages-deploy-action@4.1.4
         with: