CI/CD: Fixed bad split on flask and python version

Author: Seluj78

.github/workflows/tests.yml

@@ -30,8 +30,10 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install tox
-        tox -e py${{ matrix.python-version | replace('.', '') }}-flask${{ matrix.flask-version | replace('.', '') }}
 
     - name: Run tests
       run: |
-        tox -e py${{ matrix.python-version | replace('.', '') }}-flask${{ matrix.flask-version | replace('.', '') }}
+        PYTHON_VERSION=${{ matrix.python-version }}
+        FLASK_VERSION=${{ matrix.flask-version }}
+        TOX_ENV="py${PYTHON_VERSION//./}-flask${FLASK_VERSION//./}"
+        tox -e $TOX_ENV