Bump cryptography from 2.1.4 to 3.4.5

Bumps cryptography from 2.1.4 to 3.4.5.

Changelog

Sourced from cryptography's changelog.

3.4.5 - 2021-02-13

* Various improvements to type hints.
* Lower the minimum supported Rust version (MSRV) to >=1.41.0. This change
  improves compatibility with system-provided Rust on several Linux
  distributions.
* ``cryptography`` will be switching to a new versioning scheme with its next
  feature release. More information is available in our
  :doc:`/api-stability` documentation.

.. _v3-4-4:

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  due to outdated ``pip`` or missing ``rustc``.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
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Commits

• 4d77fb9 3.4.5 backports and changelog/version bump (#5827)
• 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)
• Additional commits viewable in compare view