gem: enable new rubocop rules, cleanup

.rubocop.yml

@@ -1,5 +1,3 @@
-inherit_from: .rubocop_todo.yml
-
 AllCops:
   TargetRubyVersion: '2.3'
 
@@ -19,6 +17,9 @@ Layout/HashAlignment:
 Layout/LeadingEmptyLines:
   Enabled: false
 
+Layout/LineLength:
+  Max: 200
+
 Layout/SpaceInsideHashLiteralBraces:
   Enabled: false
 
@@ -34,9 +35,6 @@ Metrics/ClassLength:
 Metrics/CyclomaticComplexity:
   Enabled: false
 
-Metrics/LineLength:
-  Max: 200
-
 Metrics/MethodLength:
   Enabled: false
 
@@ -64,6 +62,15 @@ Style/FrozenStringLiteralComment:
 Style/GuardClause:
   Enabled: false
 
+Style/HashEachMethods:
+  Enabled: true
+
+Style/HashTransformKeys:
+  Enabled: true
+
+Style/HashTransformValues:
+  Enabled: true
+
 Style/IdenticalConditionalBranches:
   Enabled: false
 

.rubocop_todo.yml

@@ -1,7 +0,0 @@
-# This configuration was generated by
-# `rubocop --auto-gen-config`
-# on 2018-02-23 12:54:10 +0100 using RuboCop version 0.52.1.
-# The point is for the user to remove these configuration records
-# one by one as the offenses are removed from the code base.
-# Note that changes in the inspected code, or installation of new
-# versions of RuboCop, may require this file to be generated again.