build(deps): bump h2 from 4.2.0 to 4.3.0 in /regression-tests.dnsdist
Bumps [h2](https://github.com/python-hyper/h2) from 4.2.0 to 4.3.0.
- [Changelog](https://github.com/python-hyper/h2/blob/master/CHANGELOG.rst)
- [Commits](https://github.com/python-hyper/h2/compare/v4.2.0...v4.3.0)