Update auto-deploy.yml

因为提交的pr是不可能有deploy权限的，所以只有在合并后才应该执行deploy。

.github/workflows/auto-deploy.yml

@@ -8,7 +8,6 @@ on:
 
 permissions:
   contents: write
-  pull-requests: write
 
 jobs:
   build-and-deploy:
@@ -32,6 +31,7 @@ jobs:
           hexo generate
 
       - name: deploy
+        if: github.event_name == 'push'
         uses: JamesIves/github-pages-deploy-action@v4
         with:
           folder: public