Bump rubocop from 0.52.0 to 0.52.1 (#401)

Bumps [rubocop](https://github.com/bbatsov/rubocop) from 0.52.0 to 0.52.1.
- [Release notes](https://github.com/bbatsov/rubocop/releases/tag/v0.52.1)
- [Changelog](https://github.com/bbatsov/rubocop/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop@v0.52.0...v0.52.1)

.rubocop.yml

@@ -16,9 +16,6 @@ TrivialAccessors:
 Style/ModuleFunction:
   EnforcedStyle: extend_self
 
-Style/ExtendSelf:
-  Enabled: false
-
 # https://github.com/bbatsov/rubocop/pull/72
 Style/AsciiComments:
   Enabled: false

Gemfile

@@ -9,6 +9,6 @@ gem 'overcommit', '0.41.0'
 gem 'pry', '0.11.3'
 gem 'rake', '~> 12.3'
 gem 'rake-compiler', '~> 1.0'
-gem 'rubocop', '0.52.0'
+gem 'rubocop', '0.52.1'
 gem 'simplecov', '0.15.1'
 gem 'yard', '0.9.12'

Gemfile.lock

@@ -37,7 +37,7 @@ GEM
     overcommit (0.41.0)
       childprocess (~> 0.6, >= 0.6.3)
       iniparse (~> 1.4)
-    parallel (1.12.0)
+    parallel (1.12.1)
     parser (2.4.0.2)
       ast (~> 2.3)
     powerpack (0.1.1)
@@ -49,7 +49,7 @@ GEM
     rake (12.3.0)
     rake-compiler (1.0.4)
       rake
-    rubocop (0.52.0)
+    rubocop (0.52.1)
       parallel (~> 1.10)
       parser (>= 2.4.0.2, < 3.0)
       powerpack (~> 0.1)
@@ -81,7 +81,7 @@ DEPENDENCIES
   pry (= 0.11.3)
   rake (~> 12.3)
   rake-compiler (~> 1.0)
-  rubocop (= 0.52.0)
+  rubocop (= 0.52.1)
   simplecov (= 0.15.1)
   yard (= 0.9.12)