Install pytest in dependencies

Author: flashcode

.github/workflows/tests.yml

@@ -22,6 +22,7 @@ jobs:
         sudo apt-get install gettext aspell-fr
         python -m pip install --upgrade pip
         pip install -r requirements.txt
+        pip install pytest
     - name: Lint with flake8
       run: |
         pip install flake8
@@ -36,5 +37,4 @@ jobs:
         pylint --disable=W0511,R0205 tests
     - name: Test with pytest
       run: |
-        pip install pytest
         pytest