Update python-app.yml

.github/workflows/python-app.yml

@@ -13,16 +13,18 @@ permissions:
   contents: read
 
 jobs:
-  build:
-
+  example_matrix:
     runs-on: ubuntu-latest
-
+    strategy:
+      matrix:
+        version: ["3.8", "3.9", "3.10"]
+
     steps:
     - uses: actions/checkout@v3
-    - name: Set up Python 3.10
+    - name: Set up Python ${{ matrix.version }}
       uses: actions/setup-python@v3
       with:
-        python-version: "3.10"
+        python-version: ${{ matrix.version }}
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip