use SHAs instead of versions for actions

Author: ezhang6811

.github/workflows/nightly-build.yml

@@ -21,7 +21,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v4
+      uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 #5.0.0
       with:
         fetch-depth: 0
         token: ${{ secrets.GITHUB_TOKEN }}
@@ -41,7 +41,7 @@ jobs:
         git checkout -b "$BRANCH_NAME"
     
     - name: Set up Python
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@e797f83bcb11b83ae66e0230d6156d7c80228e7c #v6.0.0
       with:
         python-version: '3.11'