Bumps [watchify](https://github.com/browserify/watchify) from 3.11.1 to 4.0.0.
- [Release notes](https://github.com/browserify/watchify/releases)
- [Changelog](https://github.com/browserify/watchify/blob/master/CHANGELOG.md)
- [Commits](https://github.com/browserify/watchify/compare/v3.11.1...v4.0.0)

---
updated-dependencies:
- dependency-name: watchify
  dependency-type: direct:development
  update-type: version-update:semver-major
...
Signed-off-by: dependabot[bot] <support@github.com>