CI: Downgrade to RuboCop 1.12 to support Ruby 2.4

Author: amotl

.rubocop.yml

@@ -4,3 +4,4 @@ require: rubocop-rspec
 
 AllCops:
   NewCops: enable
+  TargetRubyVersion: 2.4

Gemfile.lock

@@ -9,12 +9,12 @@ GEM
     ast (2.4.2)
     diff-lcs (1.4.4)
     os (1.1.1)
-    parallel (1.20.1)
-    parser (3.0.1.1)
+    parallel (1.22.1)
+    parser (3.1.3.0)
       ast (~> 2.4.1)
-    rainbow (3.0.0)
+    rainbow (3.1.1)
     rake (13.0.3)
-    regexp_parser (2.1.1)
+    regexp_parser (2.6.1)
     rexml (3.2.5)
     rspec (3.10.0)
       rspec-core (~> 3.10.0)
@@ -29,24 +29,24 @@ GEM
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.10.0)
     rspec-support (3.10.2)
-    rubocop (1.14.0)
+    rubocop (1.12.1)
       parallel (~> 1.10)
       parser (>= 3.0.0.0)
       rainbow (>= 2.2.2, < 4.0)
       regexp_parser (>= 1.8, < 3.0)
       rexml
-      rubocop-ast (>= 1.5.0, < 2.0)
+      rubocop-ast (>= 1.2.0, < 2.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 1.4.0, < 3.0)
-    rubocop-ast (1.5.0)
-      parser (>= 3.0.1.1)
+    rubocop-ast (1.23.0)
+      parser (>= 3.1.1.0)
     rubocop-rake (0.5.1)
       rubocop
     rubocop-rspec (2.3.0)
       rubocop (~> 1.0)
       rubocop-ast (>= 1.1.0)
     ruby-progressbar (1.11.0)
-    unicode-display_width (2.0.0)
+    unicode-display_width (2.3.0)
 
 PLATFORMS
   x86_64-darwin-17
@@ -59,7 +59,7 @@ DEPENDENCIES
   os
   rake
   rspec (~> 3.10)
-  rubocop
+  rubocop (< 1.13)
   rubocop-rake
   rubocop-rspec
 

crate_ruby.gemspec

@@ -60,7 +60,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'os'
   spec.add_development_dependency 'rake'
   spec.add_development_dependency 'rspec', '~> 3.10'
-  spec.add_development_dependency 'rubocop'
+  spec.add_development_dependency 'rubocop', '< 1.13'
   spec.add_development_dependency 'rubocop-rake'
   spec.add_development_dependency 'rubocop-rspec'
 end