chore(deps-dev): bump gulp and @types/gulp

Bumps [gulp](https://github.com/gulpjs/gulp) and [@types/gulp](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/gulp). These dependencies needed to be updated together.

Updates `gulp` from 3.9.1 to 4.0.2
- [Release notes](https://github.com/gulpjs/gulp/releases)
- [Changelog](https://github.com/gulpjs/gulp/blob/master/CHANGELOG.md)
- [Commits](gulpjs/gulp@v3.9.1...v4.0.2)

Updates `@types/gulp` from 4.0.13 to 4.0.17
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/gulp)

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

Signed-off-by: dependabot[bot] <[email protected]>