Add CNAME copy step in GitHub Pages workflow

Added step to copy CNAME file to book directory before deployment.

Author: bytetang

.github/workflows/gh-pages.yml

@@ -17,15 +17,18 @@ jobs:
       - name: Setup mdBook
         uses: peaceiris/actions-mdbook@v1
         with:
-          mdbook-version: '0.5.0-beta.1'  # 建议指定一个稳定版本
+          mdbook-version: '0.5.0-beta.1'  
 
       - name: Build with mdBook
         run: | 
             mdbook clean
             mdbook build
+            
+      - name: Copy CNAME to book directory
+        run: cp CNAME ./book/CNAME
 
       - name: Deploy to GitHub Pages
         uses: peaceiris/actions-gh-pages@v3
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
-          publish_dir: ./book 
+          publish_dir: ./book