ci: Upgrade actions/checkout

Author: rapsealk

.github/workflows/deploy.yml

@@ -15,7 +15,7 @@ jobs:
     needs: [lint, tests]
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set up Python 3.11
       uses: actions/setup-python@v4
       with:

.github/workflows/lint.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set up Python 3.11
       uses: actions/setup-python@v4
       with:

.github/workflows/tests.yml

@@ -28,7 +28,7 @@ jobs:
           - django: "5.1"
             python-version: "3.9"
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v4
       with: