build(deps): bump flake8 from 7.1.1 to 7.1.2 in /lib/spack/docs (#49087)

Bumps [flake8](https://github.com/pycqa/flake8) from 7.1.1 to 7.1.2.
- [Commits](https://github.com/pycqa/flake8/compare/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>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

lib/spack/docs/requirements.txt

@@ -9,5 +9,5 @@ urllib3==2.3.0
 pytest==8.3.4
 isort==6.0.0
 black==25.1.0
-flake8==7.1.1
+flake8==7.1.2
 mypy==1.11.1