Update rubocop-minitest requirement from = 0.17.2 to = 0.18.0

Updates the requirements on [rubocop-minitest](https://github.com/rubocop/rubocop-minitest) to permit the latest version.
- [Release notes](https://github.com/rubocop/rubocop-minitest/releases)
- [Changelog](https://github.com/rubocop/rubocop-minitest/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-minitest@v0.17.2...v0.18.0)

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

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

lazylead.gemspec

@@ -93,7 +93,7 @@ tasks instead of solving technical problems."
   s.add_development_dependency "random-port", "0.5.1"
   s.add_development_dependency "rdoc", "6.4.0"
   s.add_development_dependency "rubocop", "1.26.1"
-  s.add_development_dependency "rubocop-minitest", "0.17.2"
+  s.add_development_dependency "rubocop-minitest", "0.18.0"
   s.add_development_dependency "rubocop-performance", "1.13.3"
   s.add_development_dependency "rubocop-rake", "0.6.0"
   s.add_development_dependency "rubocop-rspec", "2.9.0"