Add rubocop github action step

.github/workflows/rubocop_lint.yml

@@ -0,0 +1,27 @@
+name: Lint 💎
+
+on: [push, pull_request]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Ruby 2.6 is
+      uses: actions/setup-ruby@v1
+      with:
+        ruby-version: 2.6.x
+    - uses: actions/cache@v1
+      with:
+        path: vendor/bundle
+        key: ${{ runner.os }}-gems-${{ hashFiles('**/Gemfile.lock') }}
+        restore-keys: |
+          ${{ runner.os }}-gems-
+    - name: Run Rubocop linter
+      run: |
+        gem install bundler
+        bundle config path vendor/bundle
+        bundle install --jobs 4 --retry 3
+        bundle exec rubocop

.rubocop-https---relaxed-ruby-style-rubocop-yml

@@ -1,5 +1,5 @@
 # Relaxed.Ruby.Style
-## Version 2.4
+## Version 2.5
 
 Style/Alias:
   Enabled: false
@@ -145,30 +145,9 @@ Lint/AssignmentInCondition:
   Enabled: false
   StyleGuide: https://relaxed.ruby.style/#lintassignmentincondition
 
-Metrics/AbcSize:
-  Enabled: false
-
-Metrics/BlockNesting:
-  Enabled: false
-
-Metrics/ClassLength:
-  Enabled: false
-
-Metrics/ModuleLength:
-  Enabled: false
-
-Metrics/CyclomaticComplexity:
-  Enabled: false
-
 Layout/LineLength:
   Enabled: false
 
-Metrics/MethodLength:
-  Enabled: false
-
-Metrics/ParameterLists:
-  Enabled: false
-
-Metrics/PerceivedComplexity:
+Metrics:
   Enabled: false
 

.rubocop.yml

@@ -13,3 +13,6 @@ Style/ClassVars:
 
 AllCops:
   TargetRubyVersion: 2.6
+
+Gemspec/RequiredRubyVersion:
+  Enabled: false