Bump actions/checkout from 3 to 4

.github/workflows/codeql.yml

@@ -40,7 +40,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL

.github/workflows/publish-pypi.yml

@@ -27,7 +27,7 @@ jobs:
             github.com:443
             pypi.org:443
             upload.pypi.org:443
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Set up Python
         uses: actions/setup-python@v4
         with:

.github/workflows/remove-obsolete-cache.yml

@@ -24,7 +24,7 @@ jobs:
             objects.githubusercontent.com:443
 
       - name: Check out code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Cleanup
         run: |

.github/workflows/tag-testpypi.yml

@@ -27,7 +27,7 @@ jobs:
             github.com:443
             pypi.org:443
             test.pypi.org:443
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Set up Python
         uses: actions/setup-python@v4
         with: