Release v3.0.5 - 2019-10-18

Tag release v3.0.5

References: #26, #27, #28, #29

• Upgrading - Adds support for Rails Encrypted Credentials, requiring Rails 5.2+
  and thus needed a new major version. Consequently drops support for Ruby < 2.3
  and for Rails < 5.2. Delivery method configuration changed from :aws_sdk to
  :ses, to allow for future delivery methods. Adds rubocop to the package and
  fixed many violations. This test framework now includes a dummy application for
  testing future features.