[ci] Add a test running meshroom_compute with Python 3.9

Author: cbentejac

.github/workflows/continuous-integration.yml

@@ -56,6 +56,17 @@ jobs:
       uses: codecov/test-results-action@v1
       with:
         token: ${{ secrets.CODECOV_TOKEN }}
+    - name: Set up Python 3.9 - meshroom_compute test
+      uses: actions/setup-python@v4
+      with:
+        python-version: 3.9
+    - name: Install dependencies (Python 3.9) - meshroom_compute test
+      run: |
+        python3.9 -m pip install --upgrade pip
+        python3.9 -m pip install -r requirements.txt --timeout 45
+    - name: Run imports - meshroom_compute test
+      run: |
+        PYTHONPATH=$(pwd):$PYTHONPATH python3.9 bin/meshroom_compute -h
 
   build-windows:
     runs-on: windows-latest
@@ -83,3 +94,17 @@ jobs:
       - name: Test with pytest
         run: |
           pytest tests/
+      - name: Set up Python 3.9 - meshroom_compute test
+        uses: actions/setup-python@v4
+        with:
+          python-version: 3.9
+      - name: Test version
+        run: |
+          python3 --version
+      - name: Install dependencies (Python 3.9) - meshroom_compute test
+        run: |
+          python3.9 -m pip install --upgrade pip
+          python3.9 -m pip install -r requirements.txt --timeout 45
+      - name: Run imports - meshroom_compute test
+        run: |
+          PYTHONPATH=%CD%;%PYTHONPATH% python3.9 bin/meshroom_compute -h