Fix CI

Author: Shengjie Xu

.github/workflows/ci.yml

@@ -24,10 +24,10 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@latest
+        uses: actions/checkout@v4
 
       - name: Set up Python
-        uses: actions/setup-python@latest
+        uses: actions/setup-python@v5
         with:
           python-version: '3.x'