Version 2.0 released

[fsmanuel]

The 2.0 release intends to kick off the transition to a more state of the art ember addon. It drops test coverage for ember versions before 3.4.

The main goals for upcoming 2.x releases are:

• Update the documentation to include examples for native classes
• Remove deprecations
• Make it Embroider ready
• Investigate/research opportunities native classes and tracked properties may enable

To track progress visit the issue: #335