title: not_to change.by() is not supported
body: <p>I upgraded rspec version from 2 to 3. This is one of the issues I faced:</p>
  
  <pre><code>Failures:
  
    1) Slide after .destroy(force: false) visible if .with_deleted
       Failure/Error: expect{@slide.destroy(force: false)}.to_not change(Slide.with_deleted, :count).by(1)
       NotImplementedError:
         `expect { }.not_to change { }.by()` is not supported
       # ./spec/models/slide_spec.rb:36:in `block (3 levels) in &lt;top (required)&gt;'
  </code></pre>
  
  <p>and in the <a href="https://www.relishapp.com/rspec/rspec-expectations/docs/changelog" rel="noreferrer">rspec's changelog</a> I can read it was never supported (oink ?!@#). At the same time there are still <a href="https://www.relishapp.com/rspec/rspec-expectations/v/3-0/docs/built-in-matchers" rel="noreferrer">some examples how to use change syntax</a> but without <code>not</code> keyword.</p>
  
  <p>So the question is how to expect no change ?</p>