fixed pytest action

.github/workflows/mopper-pytest.yaml

@@ -18,18 +18,20 @@ jobs:
     timeout-minutes: 60
     strategy:
       max-parallel: 5
+      matrix:
+        python-version: ["3.9", "3.10", "3.11"]
 
     steps:
     - uses: actions/[email protected]
     - name: Set up Python 3.10
       uses: actions/[email protected]
       with:
-        python-version: '3.10'
-      - name: Install Miniconda
-        uses: conda-incubator/[email protected]
-        with:
-          auto-update-conda: true
-          python-version: ${{ matrix.python-version }}
+        python-version: ${{ matrix.python-version }}
+    - name: Install Miniconda
+      uses: conda-incubator/[email protected]
+      with:
+        auto-update-conda: true
+        python-version: ${{ matrix.python-version }}
     #- name: Add conda to system path
     #  run: |
     #    # $CONDA is an environment variable pointing to the root of the miniconda directory