CI: invoke pytest with just

Author: dmerejkowsky

.github/workflows/tests.yml

@@ -29,10 +29,12 @@ jobs:
       run: |
         python -m pip install poetry
 
+    - uses: extractions/setup-just@v1
+
     - name: Prepare project for development
       run: |
-        python -m poetry install
+        just setup
 
     - name: Run tests
       run: |
-        python -m poetry run pytest --cov cli_ui
+        just test