Fix rubocop error & warnings (#187)

Author: DemetrisChr

.rubocop.yml

@@ -1,5 +1,5 @@
 inherit_from: .rubocop_todo.yml
-require:
+plugins:
   - rubocop-minitest
   - rubocop-packaging
   - rubocop-performance

.rubocop_todo.yml

@@ -31,7 +31,7 @@ Metrics/ClassLength:
 Metrics/BlockLength:
   Enabled: false
 
-Naming/PredicateName:
+Naming/PredicatePrefix:
   Enabled: false
 
 Style/AccessorGrouping:

lib/couchbase/protostellar/response_converter/search.rb

@@ -38,7 +38,7 @@ def self.to_search_result(resps, options)
 
         def self.convert_search_row(proto_row, options)
           Couchbase::Cluster::SearchRow.new do |r|
-            r.instance_variable_set(:@fields, (proto_row.fields.to_h.transform_values { |v| JSON.parse(v) }).to_json)
+            r.instance_variable_set(:@fields, proto_row.fields.to_h.transform_values { |v| JSON.parse(v) }.to_json)
             r.transcoder = options.transcoder
             r.index = proto_row.index
             r.id = proto_row.id