build(deps): bump flake8 from 7.1.1 to 7.1.2 in /book/src

Bumps [flake8](https://github.com/pycqa/flake8) from 7.1.1 to 7.1.2.
- [Commits](PyCQA/flake8@7.1.1...7.1.2)

---
updated-dependencies:
- dependency-name: flake8
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

book/src/requirements.txt

@@ -1,6 +1,6 @@
 black==24.10.0
 coverage==7.6.12
-flake8==7.1.1
+flake8==7.1.2
 hypothesis==6.125.3
 isort==5.13.2
 MutPy==0.6.1