Bump RuboCop Performance to 1.12.0

This commit bumps RuboCop Performance to 1.12.0 and suppresses
the following offense.

```console
% bundle exec rubocop -a lib/rubocop/yaml_duplication_checker.rb
Inspecting 1 file
C

Offenses:

lib/rubocop/yaml_duplication_checker.rb:26:11: C: [Corrected]
Performance/RedundantBlockCall: Use yield instead of on_duplicated.call.
          on_duplicated.call(exist, key) if exist
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

1 file inspected, 1 offense detected, 1 offense corrected
```

Gemfile

@@ -8,7 +8,7 @@ gem 'bump', require: false
 gem 'memory_profiler', platform: :mri
 gem 'rake', '~> 13.0'
 gem 'rspec', '~> 3.7'
-gem 'rubocop-performance', '~> 1.11.0'
+gem 'rubocop-performance', '~> 1.12.0'
 gem 'rubocop-rake', '~> 0.6.0'
 gem 'rubocop-rspec', '~> 2.5.0'
 # Workaround for cc-test-reporter with SimpleCov 0.18.

lib/rubocop/yaml_duplication_checker.rb

@@ -23,7 +23,7 @@ def self.traverse(tree, &on_duplicated)
       when Psych::Nodes::Mapping
         tree.children.each_slice(2).with_object([]) do |(key, value), keys|
           exist = keys.find { |key2| key2.value == key.value }
-          on_duplicated.call(exist, key) if exist
+          yield(exist, key) if exist
           keys << key
           traverse(value, &on_duplicated)
         end