Update rubocop-rake requirement from ~> 0.5.1 to ~> 0.6.0

Updates the requirements on [rubocop-rake](https://github.com/rubocop/rubocop-rake) to permit the latest version.
- [Release notes](https://github.com/rubocop/rubocop-rake/releases)
- [Changelog](https://github.com/rubocop/rubocop-rake/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-rake@v0.5.1...v0.6.0)

---
updated-dependencies:
- dependency-name: rubocop-rake
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Gemfile.lock

@@ -74,8 +74,8 @@ GEM
       unicode-display_width (>= 1.4.0, < 3.0)
     rubocop-ast (1.8.0)
       parser (>= 3.0.1.1)
-    rubocop-rake (0.5.1)
-      rubocop
+    rubocop-rake (0.6.0)
+      rubocop (~> 1.0)
     ruby-progressbar (1.11.0)
     ruby2_keywords (0.0.4)
     simplecov (0.21.2)
@@ -101,7 +101,7 @@ DEPENDENCIES
   rake (~> 13.0)
   rspec (~> 3.2)
   rubocop (~> 1.18.4)
-  rubocop-rake (~> 0.5.1)
+  rubocop-rake (~> 0.6.0)
   simplecov (~> 0.21.2)
   webmock (~> 3.1)
 

mrkt.gemspec

@@ -28,7 +28,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'rake', '~> 13.0'
   spec.add_development_dependency 'rspec', '~> 3.2'
   spec.add_development_dependency 'rubocop', '~> 1.18.4'
-  spec.add_development_dependency 'rubocop-rake', '~> 0.5.1'
+  spec.add_development_dependency 'rubocop-rake', '~> 0.6.0'
   spec.add_development_dependency 'simplecov', '~> 0.21.2'
   spec.add_development_dependency 'webmock', '~> 3.1'
 end