Update rubocop-rspec requirement from ~> 2.19 to ~> 3.0

Updates the requirements on [rubocop-rspec](https://github.com/rubocop/rubocop-rspec) to permit the latest version.
- [Release notes](https://github.com/rubocop/rubocop-rspec/releases)
- [Changelog](https://github.com/rubocop/rubocop-rspec/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-rspec@v2.19.0...v3.0.0)

---
updated-dependencies:
- dependency-name: rubocop-rspec
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile

@@ -20,7 +20,7 @@ group :tests do
   # these require special dependencies to have everything load properly
   # rubocop 1.48 supports JRuby 9.3+, which includes coverage for versions we support
   gem 'rubocop', '~> 1.48.1', require: false
-  gem 'rubocop-rspec', '~> 2.20.0', require: false
+  gem 'rubocop-rspec', '~> 3.0.0', require: false
   gem 'rubocop-performance', '~> 1.17.1', require: false
 end