Update python-pytest.yml

This PR will remove warnihgs about using old actions versions ;)

.github/workflows/python-pytest.yml

@@ -2,27 +2,20 @@
 # For more information see: https://help.github.com/actions/language-and-framework-guides/using-python-with-github-actions
 
 name: Run tests
-
 on:
   push:
     branches: [ master ]
   pull_request:
     branches: [ master ]
-
 jobs:
   build:
-
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        python-version: [3.9]
-
     steps:
-    - uses: actions/checkout@v2
-    - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v2
+    - uses: actions/checkout@v4
+    - name: Set up Python
+      uses: actions/setup-python@v5
       with:
-        python-version: ${{ matrix.python-version }}
+        python-version: 3.9
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip