Resolved Gemspec/RequiredRubyVersion
Resolved Gemspec/RequiredRubyVersion

```
index_shotgun.gemspec:16:32: C: Gemspec/RequiredRubyVersion: required_ruby_version (2.1, declared in index_shotgun.gemspec) and TargetRubyVersion (2.3, which may be specified in .rubocop.yml) should be equal.
  spec.required_ruby_version = ">= 2.1"
                               ^^^^^^^^
```

sue445/index_shotgun,sue445/index_shotgun