github actions worlkfow migrated to v4

Author: p5-vbnekit

.github/workflows/main.yml

@@ -6,13 +6,14 @@ jobs:
   flake8:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/setup-python@v3
+    - uses: actions/setup-python@v4
+      with: {python-version: 3}
     - name: Installing dependencies
       run: |
         # installing dependencies
         python -m pip install --upgrade pip
         pip install --upgrade flake8
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with: { path: snapshot }
     - name: Executing `flake8`
       run: |
@@ -22,7 +23,8 @@ jobs:
   pytest:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/setup-python@v3
+    - uses: actions/setup-python@v4
+      with: {python-version: 3}
     - name: Installing dependencies
       run: |
         # installing dependencies
@@ -45,12 +47,12 @@ jobs:
         raise RuntimeError("bad state")
         EOF
         chmod +x ./temporary/bin/unshare
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with: { path: snapshot }
     - name: Installing this package
       run: pip install --upgrade ./snapshot
     - id: cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         key: oci/examples/nginx/${{ hashFiles('snapshot/examples/nginx') }}
         path: temporary/oci
@@ -75,7 +77,7 @@ jobs:
     - if: failure()
       run: sudo tar --create --directory=temporary -- . | xz > test-context.tar.xz
     - if: failure()
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: test-context
         path: test-context.tar.xz