Remove dependency on Rake

This was only necessary for the Rake integration, which is option.
Update the documentation and remove from the gemspec.

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## master (unreleased)
 
 * Add `overflow-wrap` to `PropertySortOrder` list for SMACSS
+* Remove dependency on `rake` gem
 
 ## 0.58.0
 

Gemfile

@@ -7,6 +7,9 @@ gem 'rspec', '~> 3.8'
 # Run all pre-commit checks via Overcommit during CI runs
 gem 'overcommit', '0.49.1'
 
+# Needed to test Rake integration in specs
+gem 'rake'
+
 # Pin tool versions (which are executed by Overcommit) for Travis builds
 gem 'rubocop', '0.74.0'
 

README.md

@@ -575,7 +575,8 @@ Git hook manager, [overcommit](https://github.com/sds/overcommit).
 
 ## Rake Integration
 
-To execute `scss-lint` via a [Rake](https://github.com/ruby/rake) task, add the
+To execute `scss-lint` via a [Rake](https://github.com/ruby/rake) task, ensure
+you have `rake` in your gem path (e.g. by adding to your `Gemfile`), and add the
 following to your `Rakefile`:
 
 ```ruby

scss_lint.gemspec

@@ -25,6 +25,5 @@ Gem::Specification.new do |s|
 
   s.required_ruby_version = '>= 2.4'
 
-  s.add_dependency 'rake', '>= 0.9', '< 13'
   s.add_dependency 'sass', '~> 3.5', '>= 3.5.5'
 end