Update bundler requirement from ~> 1.17.1 to ~> 2.0.1

Updates the requirements on [bundler](https://github.com/bundler/bundler) to permit the latest version.
- [Release notes](https://github.com/bundler/bundler/releases)
- [Changelog](https://github.com/bundler/bundler/blob/v2.0.1/CHANGELOG.md)
- [Commits](https://github.com/bundler/bundler/commits/v2.0.1

)

Signed-off-by: dependabot[bot] <support@dependabot.com>