build(deps-dev): bump phpunit/phpunit in /build/integration

Bumps [phpunit/phpunit](https://github.com/sebastianbergmann/phpunit) from 9.6.18 to 9.6.19.
- [Release notes](https://github.com/sebastianbergmann/phpunit/releases)
- [Changelog](https://github.com/sebastianbergmann/phpunit/blob/9.6.19/ChangeLog-9.6.md)
- [Commits](sebastianbergmann/phpunit@9.6.18...9.6.19)

---
updated-dependencies:
- dependency-name: phpunit/phpunit
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]