Log Message:
py-nacl: updated to 1.4.0

1.4.0:
* Update ``libsodium`` to 1.0.18.
* **BACKWARDS INCOMPATIBLE:** We no longer distribute 32-bit ``manylinux1``
  wheels. Continuing to produce them was a maintenance burden.
* Added support for Python 3.8, and removed support for Python 3.4.
* Add low level bindings for extracting the seed and the public key
  from crypto_sign_ed25519 secret key
* Add low level bindings for deterministic random generation.
* Add ``wheel`` and ``setuptools`` setup_requirements in ``setup.py``
* Fix checks on very slow builders
* Add low-level bindings to ed25519 arithmetic functions
* Update low-level blake2b state implementation
* Fix wrong short-input behavior of SealedBox.decrypt()
* Raise CryptPrefixError exception instead of InvalidkeyError when trying
  to check a password against a verifier stored in a unknown format
* Add support for minimal builds of libsodium. Trying to call functions
  not available in a minimal build will raise an UnavailableError
  exception. To compile a minimal build of the bundled libsodium, set
  the SODIUM_INSTALL_MINIMAL environment variable to any non-empty
  string (e.g. ``SODIUM_INSTALL_MINIMAL=1``) for setup.