Update cryptography to 3.4.4

[pyup-bot]

This PR updates cryptography from 3.3.1 to 3.4.4.

Changelog

3.4.4

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

* Added a ``py.typed`` file so that ``mypy`` will know to use our type
annotations.
* Fixed an import cycle that could be triggered by certain import sequences.

.. _v3-4-3:

3.4.3

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

* Specify our supported Rust version (>=1.45.0) in our ``setup.py`` so users
on older versions will get a clear error message.

.. _v3-4-2:

3.4.2

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

* Improvements to make the rust transition a bit easier. This includes some
better error messages and small dependency fixes. If you experience
installation problems **Be sure to update pip** first, then check the
:doc:`FAQ </faq>`.

.. _v3-4-1:

3.4.1

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

* Fixed a circular import issue.
* Added additional debug output to assist users seeing installation errors
due to outdated ``pip`` or missing ``rustc``.

.. _v3-4:

3.4

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

* **BACKWARDS INCOMPATIBLE:** Support for Python 2 has been removed.
* We now ship ``manylinux2014`` wheels and no longer ship ``manylinux1``
wheels. Users should upgrade to the latest ``pip`` to ensure this doesn't
cause issues downloading wheels on their platform.
* ``cryptography`` now incorporates Rust code. Users building ``cryptography``
themselves will need to have the Rust toolchain installed. Users who use an
officially produced wheel will not need to make any changes. The minimum
supported Rust version is 1.45.0.
* ``cryptography`` now has :pep:`484` type hints on nearly all of of its public
APIs. Users can begin using them to type check their code with ``mypy``.

.. _v3-3-2:

3.3.2

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

* **SECURITY ISSUE:** Fixed a bug where certain sequences of ``update()`` calls
when symmetrically encrypting very large payloads (>2GB) could result in an
integer overflow, leading to buffer overflows. *CVE-2020-36242*

.. _v3-3-1:

Links

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