Update bundler requirement from ~> 1.15 to ~> 2.2
Update bundler requirement from ~> 1.15 to ~> 2.2

Updates the requirements on [bundler](https://github.com/rubygems/rubygems) to permit the latest version.
- [Release notes](https://github.com/rubygems/rubygems/releases)
- [Changelog](https://github.com/rubygems/rubygems/blob/master/bundler/CHANGELOG.md)
- [Commits](https://github.com/rubygems/rubygems/compare/v1.15.0...bundler-v2.2.5)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
juicyparts/capistrano-rpush