pip: bump google-auth from 2.55.1 to 2.56.2

Bumps [google-auth](https://github.com/googleapis/google-cloud-python) from 2.55.1 to 2.56.2.
- [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@google-auth-v2.55.1...google-auth-v2.56.2)

---
updated-dependencies:
- dependency-name: google-auth
  dependency-version: 2.56.2
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Author: dependabot[bot]

requirements.txt

@@ -18,7 +18,7 @@ google-cloud-ndb==2.5.0
 google-cloud-logging==3.16.1
 google-cloud-secret-manager==2.30.0
 google-cloud-storage==3.13.0
-google-auth==2.55.1
+google-auth==2.56.2
 google-genai==2.12.1
 requests==2.34.2
 redis==7.4.0