Allow a recent version of Rubocop

Than old version of Rubocop only work with an outdated version of Ruby.
With modern Ruby, we need a more recent version of Rubocop.  Adjust the
configuration accordingly and ignore the new borring offenses.

.rubocop.yml

@@ -23,9 +23,6 @@ Style/TrailingUnderscoreVariable:
 Lint/NonLocalExitFromIterator:
   Enabled: false
 
-Style/TrailingUnderscoreVariable:
-  Enabled: false
-
 Naming/ClassAndModuleCamelCase:
   Enabled: false
 
@@ -68,9 +65,6 @@ Layout/SpaceInsideBlockBraces:
 Layout/SpaceInsideHashLiteralBraces:
   EnforcedStyle: no_space
 
-Style/Documentation:
-  Severity: warning
-
 Style/EachWithObject:
   Enabled: false
 
@@ -104,7 +98,7 @@ Lint/UnusedMethodArgument:
 Lint/AssignmentInCondition:
   Enabled: false
 
-Metrics/LineLength:
+Layout/LineLength:
   Max: 180
 
 Metrics/PerceivedComplexity:
@@ -131,9 +125,6 @@ Metrics/ModuleLength:
 Metrics/BlockLength:
   Enabled: false
 
-Performance/Casecmp:
-  Enabled: false
-
 Style/FrozenStringLiteralComment:
   Enabled: false
 
@@ -143,21 +134,33 @@ Style/SymbolArray:
 Security/MarshalLoad:
   Enabled: false
 
-Layout/IndentHeredoc:
+Layout/HeredocIndentation:
   Enabled: false
 
-# @todo use safe_load but its a big change
-Security/YAMLLoad:
+Layout/HashAlignment:
   Enabled: false
 
-Performance/RegexpMatch:
+Style/FormatStringToken:
   Enabled: false
 
-Style/SafeNavigation:
+Style/RedundantBegin:
   Enabled: false
 
-Lint/RescueWithoutErrorClass:
+Style/IfUnlessModifier:
+  Enabled: false
+
+Naming/MethodParameterName:
+  Enabled: false
+
+Lint/ConstantDefinitionInBlock:
+  Enabled: false
+
+# @todo use safe_load but its a big change
+Security/YAMLLoad:
+  Enabled: false
+
+Style/SafeNavigation:
   Enabled: false
 
-Performance/StringReplacement:
+Style/RescueStandardError:
   Enabled: false

Gemfile

@@ -7,7 +7,7 @@ group :test do
   gem "mocha"
   gem "rake"
   gem "rspec"
-  gem "rubocop", "0.51.0"
+  gem "rubocop"
   gem "sys-proctable"
 end
 
@@ -16,5 +16,5 @@ mcollective_version = ENV["MCOLLECTIVE_GEM_VERSION"]
 if mcollective_version
   gem "mcollective-client", mcollective_version, :require => false
 else
-  gem "mcollective-client", :require => false # rubocop:disable Bundler/DuplicatedGem
+  gem "mcollective-client", :require => false
 end