Update rubocop requirement from ~> 0.84.0 to ~> 0.85.0

Updates the requirements on [rubocop](https://github.com/rubocop-hq/rubocop) to permit the latest version.
- [Release notes](https://github.com/rubocop-hq/rubocop/releases)
- [Changelog](https://github.com/rubocop-hq/rubocop/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop@v0.84.0...v0.85.0)

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

Gemfile

@@ -7,7 +7,7 @@ gem 'coveralls'
 gem 'rake'
 gem 'rspec', '~> 3.0'
 gem 'rspec-rails'
-gem 'rubocop', '~> 0.84.0'
+gem 'rubocop', '~> 0.85.0'
 
 gem 'rails'
 gem 'sqlite3'