Update python-app.yml

Update workflow to use proper versions for build scripts.

Author: craigthomas

.github/workflows/python-app.yml

@@ -2,22 +2,22 @@ name: Build Test Coverage
 on: [push, pull_request]
 jobs:
   run:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     env:
-      OS: ubuntu-latest
-      PYTHON: '3.6.8'
+      OS: ubuntu-20.04
+      PYTHON: '3.8.10'
       DISPLAY: :0
     steps:
     - name: Checkout
-      uses: actions/checkout@v2.3.4
+      uses: actions/checkout@v3
     - name: Setup Python
-      uses: actions/setup-python@v2.2.2
+      uses: actions/setup-python@v4
       with:
-        python-version: 3.6.8
+        python-version: 3.8.10
     - name: Generate Report
       run: |
         pip install -r requirements.txt
         sudo apt-get install xvfb
         xvfb-run --auto-servernum coverage run --source=chip8 -m unittest
     - name: Codecov
-      uses: codecov/codecov-action@v1.5.2
+      uses: codecov/codecov-action@v3.1.0