Add check-only pre-commit style gate with flake8

.pre-commit-config.yaml

@@ -0,0 +1,10 @@
+repos:
+  - repo: https://github.com/pycqa/flake8
+    rev: 6.0.0
+    hooks:
+      - id: flake8
+        args:
+          - --count
+          - --max-complexity=10
+          - --max-line-length=127
+          - --statistics

README.md

@@ -56,6 +56,17 @@ To test the package, you can use the following command:
 pytest
 ```
 
+To enable style checks before every commit, install the development dependencies and
+set up the git pre-commit hook:
+
+```bash
+pip install -r requirements-dev.txt
+pre-commit install
+```
+
+Then pre-commit will run `flake8` as a check-only step. It reports failures and
+does not automatically rewrite files.
+
 ## How can I contact you?
 
 You can open a new discussion in this repository's [Discussion](https://github.com/alifa98/GameKit/discussions) section for any question.

requirements-dev.txt

@@ -1,4 +1,5 @@
 build==0.10.0
 flake8==6.0.0
+pre-commit==3.8.0
 pytest==7.4.0
 twine==4.0.2