build(deps-dev): bump gcovr from 8.5 to 8.6 in the python group

Bumps the python group with 1 update: [gcovr](https://github.com/gcovr/gcovr).


Updates `gcovr` from 8.5 to 8.6
- [Release notes](https://github.com/gcovr/gcovr/releases)
- [Changelog](https://github.com/gcovr/gcovr/blob/main/CHANGELOG.rst)
- [Commits](gcovr/gcovr@8.5...8.6)

---
updated-dependencies:
- dependency-name: gcovr
  dependency-version: '8.6'
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: python
...

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Author: dependabot[bot]