Bump @types/gulp from 4.0.8 to 4.0.9

Bumps [@types/gulp](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/gulp) from 4.0.8 to 4.0.9.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/gulp)

---
updated-dependencies:
- dependency-name: "@types/gulp"
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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