simplify workflow

Author: corsicanec82

.github/workflows/pyci.yml

@@ -12,17 +12,13 @@ jobs:
   build:
     runs-on: ubuntu-latest
 
-    strategy:
-      matrix:
-        python-version: [3.8, 3.9]
-
     steps:
       - uses: actions/checkout@v2
 
-      - name: Set up Python ${{ matrix.python-version }}
+      - name: Set up Python
         uses: actions/setup-python@v2
         with:
-          python-version: ${{ matrix.python-version }}
+          python-version: '3.8'
 
       - name: Install dependencies
         run: |