Django-pgcrypto-fields

* Added support for Django 3.1.x
* Updated requirements_dev.txt
* Dropped support for Python 3.5
* Dropped support for Django below 2.2.x LTS release
* Added support for BigIntegerFields (169)
* Added documentation for migration existing data (246)

* Added support for Django 3.x
* Updated requirements_dev.txt

* Fixed regression in the definition of EmailPGPPublicKeyField (77)
* Removed dead code (remove_validators and RemoveMaxLengthValidatorMixin)
* Updated requirements_dev.txt

* Added new DecimalFields for both public and symmetric key (64)
* Added new FloatFields for both public and symmetric key (64)
* Added new TimeFields for both public and symmetric key (64)
* Added support for different keys based on database (67)

* Added auto-decryption of all encrypted fields including FK tables
* Removed django-pgcrypto-fields `aggregates`, `PGPManager` and `PGPAdmin` as they are no longer needed
* Added support for `get_or_create()` and `update_or_create()` (27)
* Added support for `get_by_natural_key()` (23)
* Added support for `only()` and `defer()` as they were not supported with `PGPManager`
* Added support for `distinct()` (Django 2.1+ with workaround available for 2.0 and lower)
* Separated out dev requirements from setup.py requirements
* Updated packaging / setup.py to include long description
* Added AUTHORS and updated CONTRIBUTING
* Updated TravisCI to use Xenial to gain Python 3.7 in the matrix