v0.3.0

First release candidate for 0.3.x series.
Updates:

Includes support for two new testing libraries, utest and minitest.
The monix.testing.scalatest.AsyncTaskSpec has been renamed to *.MonixTaskTest, in order to be consistent with the rest of testing frameworks.
It also includes documentation on how to getting started, including with testing monix Task with specs2, which directly uses cats-effect-testing.

v0.3.0-RC1

Improve readme

Scalafmt