Update contributing

Author: Neraste

CONTRIBUTING.md

@@ -57,10 +57,10 @@ You need to call isort before committing changes.
 ### Code style
 
 The code follows the [PEP8](https://www.python.org/dev/peps/pep-0008/) style guide (88 characters per line).
-Quality of code is checked with [Flake8](https://pypi.org/project/flake8/):
+Quality of code is checked with [Ruff](https://pypi.org/project/ruff/):
 
 ```sh
-flake8
+ruff check .
 ```
 
 Style is enforced using [Black](https://github.com/ambv/black):