Update pyopenssl to 19.0.0

[pyup-bot]

This PR updates pyOpenSSL from 18.0.0 to 19.0.0.

Changelog

19.0.0

-------------------


Backward-incompatible changes:
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

- ``X509Store.add_cert`` no longer raises an error if you add a duplicate cert.
`787 <https://github.com/pyca/pyopenssl/pull/787>`_


Deprecations:
^^^^^^^^^^^^^

*none*


Changes:
^^^^^^^^

- pyOpenSSL now works with OpenSSL 1.1.1.
`805 <https://github.com/pyca/pyopenssl/pull/805>`_
- pyOpenSSL now handles NUL bytes in ``X509Name.get_components()``
`804 <https://github.com/pyca/pyopenssl/pull/804>`_



----

Links

• PyPI: https://pypi.org/project/pyopenssl
• Changelog: https://pyup.io/changelogs/pyopenssl/
• Homepage: https://pyopenssl.org/
• Docs: https://pythonhosted.org/pyOpenSSL/