title: Rubocop: Is it possible to add exclusions to Metrics/AbcSize cop?
body: <p>Let's consider the following class:</p>
  
  <pre class="lang-rb prettyprint-override"><code>class App
    def call
      # ...
    end
  
    private
  
    def foo
      # ...
    end
  
    def bar
      # ... 
    end
  end
  </code></pre>
  
  <p>Is it possible to configure <code>rubocop</code> to 'complain' about <code>Metrics/AbcSize</code> for all methods when <code>Assignment Branch Condition size</code> is higher than 15 with an exception for <code>call</code> methods?</p>
  
  <p>For <code>call</code> methods it should 'complain' only if <code>Assignment Branch Condition size</code> is higher than 30.</p>
  
  <p>Thanks in advance.</p>