title: Supporting extra quotes around Unicode is deprecated in traitlets 5.0
body: <p>Issue:</p>
  <p><code>Kernel died with exit code 1073741845</code></p>
  <p>1.</p>
  <pre><code>c:\anaconda\envs\my_env\lib\site-packages\traitlets\ traitlets.py :2196: FutureWarning: Supporting extra quotes around Unicode is deprecated in traitlets 5.0. Use 'hmac-sha256' instead of '&quot;hmac-sha256&quot;' – or use CUnicode.
  </code></pre>
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  </ol>
  <pre><code>warn( c:\anaconda\envs\my_env\lib\site-packages\traitlets\traitlets.py:2151: FutureWarning: Supporting extra quotes around Bytes is deprecated in traitlets 5.0. Use '7aa5b615-129a-4e47-b483-0954be3b7001' instead of 'b&quot;7aa5b615-129a-4e47-b483-0954be3b7001&quot;'.
  </code></pre>
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  </ol>
  <pre><code>warn( Bad file descriptor (bundled\zeromq\src\epoll.cpp:100)
  </code></pre>