ci: don't install in editable mode (conflict with pyproject.toml and …

…pyinstaller?)

.github/workflows/check.yml

@@ -39,7 +39,7 @@ jobs:
         python -m pip install coverage flake8
         python -m pip install -r tests/requirements.txt
         # install dependencies
-        pip install -e .[GUI]
+        pip install .[GUI]
         # show installed packages
         pip freeze
     - name: Start application and print version