Add isort to dev dependencies

setup.py

@@ -23,7 +23,7 @@ setup(
     },
     install_requires=[],
     extras_require={
-        "dev": ["black", "pylint", "mypy"],
+        "dev": ["black", "pylint", "mypy", "isort"],
         "server": ["Flask", "SQLAlchemy", "Flask-SQLAlchemy", "alembic", "uwsgi"],
         "client": ["PySide2", "qdarkstyle>=2.6.0", "requests", "simpleaudio"],
         "osk": ["dbus-python"],