Add flake8 back to pre-commit setup

It was accidenteally removed in 1c44e6b

Author: ulgens

.pre-commit-config.yaml

@@ -4,3 +4,8 @@ repos:
     hooks:
     -   id: pyupgrade
         args: ["--py310-plus"]
+
+-   repo: https://github.com/pycqa/flake8
+    rev: 7.3.0
+    hooks:
+    -   id: flake8