Bump phpunit/phpunit in the composer group across 1 directory

Bumps the composer group with 1 update in the / directory: [phpunit/phpunit](https://github.com/sebastianbergmann/phpunit).


Updates `phpunit/phpunit` from 9.6.20 to 9.6.33
- [Release notes](https://github.com/sebastianbergmann/phpunit/releases)
- [Changelog](https://github.com/sebastianbergmann/phpunit/blob/9.6.33/ChangeLog-9.6.md)
- [Commits](sebastianbergmann/phpunit@9.6.20...9.6.33)

---
updated-dependencies:
- dependency-name: phpunit/phpunit
  dependency-version: 9.6.33
  dependency-type: direct:development
  dependency-group: composer
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]