Bump @google-cloud/functions-framework in /scripts/gcb2slack (#3706)

Bumps [@google-cloud/functions-framework](https://github.com/GoogleCloudPlatform/functions-framework-nodejs) from 3.4.2 to 3.4.3.
- [Release notes](https://github.com/GoogleCloudPlatform/functions-framework-nodejs/releases)
- [Changelog](https://github.com/GoogleCloudPlatform/functions-framework-nodejs/blob/main/CHANGELOG.md)
- [Commits](GoogleCloudPlatform/functions-framework-nodejs@v3.4.2...v3.4.3)

---
updated-dependencies:
- dependency-name: "@google-cloud/functions-framework"
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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