style: add rubocop 1.9 cops (#8567)

Merge pull request 8567

.rubocop.yml

@@ -109,6 +109,10 @@ Lint/NestedPercentLiteral:
     - test/test_site.rb
 Lint/NoReturnInBeginEndBlocks:
   Enabled: true
+Lint/NumberedParameterAssignment:
+  Enabled: true
+Lint/OrAssignmentToConstant:
+  Enabled: true
 Lint/OutOfRangeRegexpRef:
   Enabled: true
 Lint/RaiseException:
@@ -121,12 +125,16 @@ Lint/SelfAssignment:
   Enabled: true
 Lint/StructNewOverride:
   Enabled: true
+Lint/SymbolConversion:
+  Enabled: true
 Lint/ToEnumArguments:
   Enabled: false
 Lint/TopLevelReturnWithArgument:
   Enabled: true
 Lint/TrailingCommaInAttributeDeclaration:
   Enabled: true
+Lint/TripleQuotes:
+  Enabled: true
 Lint/UnexpectedBlockArity:
   Enabled: true
 Lint/UnmodifiedReduceAccumulator:
@@ -321,6 +329,8 @@ Style/HashTransformKeys:
   Enabled: false
 Style/HashTransformValues:
   Enabled: true
+Style/IfWithBooleanLiteralBranches:
+  Enabled: true
 Style/KeywordParametersOrder:
   Enabled: true
 Style/MixinUsage:

Gemfile

@@ -23,7 +23,7 @@ group :test do
   gem "nokogiri", "~> 1.7"
   gem "rspec"
   gem "rspec-mocks"
-  gem "rubocop", "~> 1.8.1"
+  gem "rubocop", "~> 1.9.1"
   gem "rubocop-minitest"
   gem "rubocop-performance"
   gem "rubocop-rake"