Update cryptography to 2.7

[pyup-bot]

This PR updates cryptography from 2.6.1 to 2.7.

Changelog

2.7

~~~~~~~~~~~~~~~~

* **BACKWARDS INCOMPATIBLE:** We no longer distribute 32-bit ``manylinux1``
wheels. Continuing to produce them was a maintenance burden.
* **BACKWARDS INCOMPATIBLE:** Removed the
``cryptography.hazmat.primitives.mac.MACContext`` interface. The ``CMAC`` and
``HMAC`` APIs have not changed, but they are no longer registered as
``MACContext`` instances.
* Removed support for running our tests with ``setup.py test``. Users
interested in running our tests can continue to follow the directions in our
:doc:`development documentation</development/getting-started>`.
* Add support for :class:`~cryptography.hazmat.primitives.poly1305.Poly1305`
when using OpenSSL 1.1.1 or newer.
* Support serialization with ``Encoding.OpenSSH`` and ``PublicFormat.OpenSSH``
in
:meth:`Ed25519PublicKey.public_bytes
<cryptography.hazmat.primitives.asymmetric.ed25519.Ed25519PublicKey.public_bytes>`
.
* Correctly allow passing a ``SubjectKeyIdentifier`` to
:meth:`~cryptography.x509.AuthorityKeyIdentifier.from_issuer_subject_key_identifier`
and deprecate passing an ``Extension`` object. The documentation always
required ``SubjectKeyIdentifier`` but the implementation previously
required an ``Extension``.

.. _v2-6-1:

Links

• PyPI: https://pypi.org/project/cryptography
• Changelog: https://pyup.io/changelogs/cryptography/
• Repo: https://github.com/pyca/cryptography

[pyup-bot]

Closing this in favor of #344