build(deps): bump coverage from 7.9.0 to 7.9.1 in /book/src

Bumps [coverage](https://github.com/nedbat/coveragepy) from 7.9.0 to 7.9.1.
- [Release notes](https://github.com/nedbat/coveragepy/releases)
- [Changelog](https://github.com/nedbat/coveragepy/blob/master/CHANGES.rst)
- [Commits](coveragepy/coveragepy@7.9.0...7.9.1)

---
updated-dependencies:
- dependency-name: coverage
  dependency-version: 7.9.1
  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

@@ -1,5 +1,5 @@
 black==24.10.0
-coverage==7.9.0
+coverage==7.9.1
 flake8==7.1.2
 hypothesis==6.135.9
 isort==5.13.2