Update cryptography to 1.9

[pyup-bot]

There's a new version of cryptography available.
You are currently using 1.8.2. I have updated it to 1.9

These links might come in handy: PyPI | Changelog | Repo

Changelog

1.9

• BACKWARDS INCOMPATIBLE: Elliptic Curve signature verification no longer
  returns True on success. This brings it in line with the interface's
  documentation, and our intent. The correct way to use
  :meth:~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicKey.verify
  has always been to check whether or not
  :class:~cryptography.exceptions.InvalidSignature was raised.
• BACKWARDS INCOMPATIBLE: Dropped support for macOS 10.7 and 10.8.
• BACKWARDS INCOMPATIBLE: The minimum supported PyPy version is now 5.3.
• Python 3.3 support has been deprecated, and will be removed in the next
  cryptography release.
• Add support for providing tag during
  :class:~cryptography.hazmat.primitives.ciphers.modes.GCM finalization via
  :meth:~cryptography.hazmat.primitives.ciphers.AEADDecryptionContext.finalize_with_tag.
• Fixed an issue preventing cryptography from compiling against
  LibreSSL 2.5.x.
• Added
  :meth:~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicKey.key_size
  and
  :meth:~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePrivateKey.key_size
  as convenience methods for determining the bit size of a secret scalar for
  the curve.
• Accessing an unrecognized extension marked critical on an X.509 object will
  no longer raise an UnsupportedExtension exception, instead an
  :class:~cryptography.x509.UnrecognizedExtension object will be returned.
  This behavior was based on a poor reading of the RFC, unknown critical
  extensions only need to be rejected on certificate verification.
• The CommonCrypto backend has been removed.
• MultiBackend has been removed.
• Whirlpool and RIPEMD160 have been deprecated.

Got merge conflicts? Close this PR and delete the branch. I'll create a new PR for you.

Happy merging! 🤖