Bump google-cloud-pubsub from 2.25.2 to 2.26.0 (#163)

Bumps [google-cloud-pubsub](https://github.com/googleapis/python-pubsub) from 2.25.2 to 2.26.0.
- [Release notes](https://github.com/googleapis/python-pubsub/releases)
- [Changelog](https://github.com/googleapis/python-pubsub/blob/main/CHANGELOG.md)
- [Commits](googleapis/python-pubsub@v2.25.2...v2.26.0)

---
updated-dependencies:
- dependency-name: google-cloud-pubsub
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

event-handler/requirements.txt

@@ -1,4 +1,4 @@
 Flask==3.0.3
 gunicorn==23.0.0
-google-cloud-pubsub==2.25.2
+google-cloud-pubsub==2.26.0
 google-cloud-secret-manager==2.20.2