docs: bump version in example code

Author: exuanbo

README.md

@@ -7,7 +7,7 @@
 ```yml
 - uses: actions/checkout@v2
 - name: Deploy
-  uses: exuanbo/[email protected].2
+  uses: exuanbo/[email protected].3
   with:
     token: ${{ secrets.TOKEN }}
     gist_id: from_your_gist_url