fix(rubocop): Fix Layout/LineLength

- bump rubocop to v1.0
- Fix Layout/MultilineAssignmentLayout and other remaining offences
- Exculde appraisal generated gemfiles in rubocop
- Replace NON_NUMERIC_VALUE constant with instance method against 
failing test case in  rails <= 5.1 and postgres adapter.
This is a defect in rails where a frozen string is modified in 
https://github.com/rails/rails/blob/v5.1.7/activerecord/lib/active_record/connection_adapters/postgresql/oid/money.rb#L25

lib/shoulda/matchers/action_controller/callback_matcher.rb

@@ -179,11 +179,13 @@ module Shoulda
         end
 
         def failure_message
-          "Expected that #{controller_class.name} would have :#{method_name} as a #{kind}_#{callback_type}"
+          "Expected that #{controller_class.name} would have :#{method_name}"\
+            " as a #{kind}_#{callback_type}"
         end
 
         def failure_message_when_negated
-          "Expected that #{controller_class.name} would not have :#{method_name} as a #{kind}_#{callback_type}"
+          "Expected that #{controller_class.name} would not have"\
+            " :#{method_name} as a #{kind}_#{callback_type}"
         end
 
         def description