Bump cryptography from 2.1.4 to 3.4.4

Bumps cryptography from 2.1.4 to 3.4.4.

Changelog

Sourced from cryptography's changelog.

3.4.4 - 2021-02-09

* 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 - 2021-02-08

• 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 - 2021-02-08

* 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 - 2021-02-07

• 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• Added additional debug output to assist users seeing installation errors due to outdated pip or missing rustc.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 - 2021-02-07

* **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``.

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Commits

• 4a3018e 3.4.4 - backports, changelog, and version bumps (#5803)
• 86c9e4a version bump, changelog already done (#5791)
• 0f40cb3 [3.4] Specify an MSRV in setup.py (#5789) (#5790)
• 74a3df4 3.4.2 changelog and version bump (#5784)
• 4a66e2b [3.4] More aggressively point people at Rust version docs (#5782) (#5783)
• 843ada6 Remove setuptools_rust from install requirement (#5779) (#5781)
• e5b5c3d Interface: Make annotation check optional (#5775) (#5780)
• ebde3be 3.4.1 fixes and changelog bump (#5761)
• 2c11ad5 3.4 release (#5749)
• 06cbf77 port changelog and fix back to master for CVE-2020-36242 (#5748)
• Additional commits viewable in compare view