PyCA cryptography 2.2 released

[Paul Kehrer]

PyCA cryptography 2.2 has been released to PyPI. cryptography includes both
high level recipes and low level interfaces to common cryptographic
algorithms such as symmetric ciphers, message digests, and key derivation
functions. We support Python 2.7, Python 3.4+, and PyPy.

Changelog (https://cryptography.io/en/latest/changelog/#v2-2):

* BACKWARDS INCOMPATIBLE: Support for Python 2.6 has been dropped. The last
version of cryptography that supports Python 2.6 is 2.1.4.
* Resolved a bug in HKDF that incorrectly constrained output size.
* Added BrainpoolP256R1, BrainpoolP384R1, and BrainpoolP512R1 to support
inter-operating with systems like German smart meters.
* Added token rotation support to Fernet with rotate().
* Fixed a memory leak in derive_private_key().
* Added support for AES key wrapping with padding via
aes_key_wrap_with_padding() and aes_key_unwrap_with_padding() .
* Allow loading DSA keys with 224 bit q.

Thanks to everyone who contributed!

-Paul Kehrer (reaperhulk)