Bump @google-cloud/pubsub from 4.0.7 to 4.5.0

Bumps [@google-cloud/pubsub](https://github.com/googleapis/nodejs-pubsub) from 4.0.7 to 4.5.0.
- [Release notes](https://github.com/googleapis/nodejs-pubsub/releases)
- [Changelog](https://github.com/googleapis/nodejs-pubsub/blob/main/CHANGELOG.md)
- [Commits](googleapis/nodejs-pubsub@v4.0.7...v4.5.0)

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

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Author: dependabot[bot]