Suppress RuboCop's warning and offense

This PR suppresses the following RuboCop's warning and offense:

```console
$ bundle exec rubocop rake
(snip)

Warning: Using `Naming/PredicateName` configuration in /Users/koic/src/github.com/rubocop/rubocop-rails/.rubocop.yml for `Naming/PredicatePrefix`.

(snip)

Offenses:

lib/rubocop/cop/rails/save_bang.rb:230:13: C: Naming/PredicateMethod: Predicate method names should end with ?.
        def check_used_in_condition_or_compound_boolean(node)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

301 files inspected, 1 offense detected
```

Author: koic

.rubocop.yml

@@ -47,7 +47,7 @@ Naming/InclusiveLanguage:
     - spec/rubocop/cop/rails/dynamic_find_by_spec.rb
     - spec/rubocop/cop/rails/skips_model_validations_spec.rb
 
-Naming/PredicateName:
+Naming/PredicatePrefix:
   # Method define macros for dynamically generated method.
   MethodDefinitionMacros:
     - define_method

lib/rubocop/cop/rails/save_bang.rb

@@ -156,7 +156,7 @@ def on_send(node)
           return unless persist_method?(node)
           return if return_value_assigned?(node)
           return if implicit_return?(node)
-          return if check_used_in_condition_or_compound_boolean(node)
+          return if check_used_in_condition_or_compound_boolean?(node)
           return if argument?(node)
           return if explicit_return?(node)
           return if checked_immediately?(node)
@@ -227,7 +227,7 @@ def array_parent(node)
           array
         end
 
-        def check_used_in_condition_or_compound_boolean(node)
+        def check_used_in_condition_or_compound_boolean?(node)
           return false unless in_condition_or_compound_boolean?(node)
 
           register_offense(node, CREATE_CONDITIONAL_MSG) unless MODIFY_PERSIST_METHODS.include?(node.method_name)