title: Conflict when running Bundle update among gem dependencies using equals-to and twiddle-wakka against the same version
body: <p>Running across this issue using Bundle Update. Shouldn't the tilde-greater-than or twiddle-wakka and equals-to both resolve to 5.1.0?</p>
  
  <pre><code>Bundler could not find compatible versions for gem "actionmailer":
        In Gemfile:
          rails (= 5.1) was resolved to 5.1.0, which depends on
            actionmailer (= 5.1.0)
  
          solidus_core (~&gt; 2.5.0) was resolved to 2.5.0, which depends on
            actionmailer (~&gt; 5.1.0)
  </code></pre>
  
  <p>Any pointers are appreciated. Thanks.</p>