chore(deps): bump googleapis-common-protos from 1.67.0 to 1.68.0 (#545)

Bumps [googleapis-common-protos](https://github.com/googleapis/google-cloud-python) from 1.67.0 to 1.68.0.
- [Release notes](https://github.com/googleapis/google-cloud-python/releases)
- [Changelog](https://github.com/googleapis/google-cloud-python/blob/main/packages/google-cloud-documentai/CHANGELOG.md)
- [Commits](googleapis/google-cloud-python@googleapis-common-protos-v1.67.0...googleapis-common-protos-v1.68.0)

---
updated-dependencies:
- dependency-name: googleapis-common-protos
  dependency-type: indirect
  update-type: version-update:semver-minor
...

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Co-authored-by: clement <clement.boussiron@gmail.com>