Update test dependencies to newer versions

[ILikeYourHat]

Hello 👋 I found your plugin very interesting and I want to use it in my company's project. But before this would happen, I must be sure that it is still well maintained and there would be no issues during future collaboration, like submitting bugs or accepting changes from community. So I've prepared a small contribution, I would be very happy if you accept it and prove that this plugin is still getting some love by it's creators 😉

Changes:

• bump com.google.truth:truth to 1.4.2 (IntelliJ reported that the previous version had some security vulnerabilities)
  • afaik no additional changes were necessary because of it
• replace com.nhaarman:mockito-kotlin with org.mockito.kotlin:mockito-kotlin
  • Nhaarman's library was integrated into official Mockito organization, see link
  • the newest version of this library is 5.X. However, this major version requires Java 11, and your project is still on Java 8. Because of this, I've updated mockito-kotlin only to the 4.X version, which is still compatible with Java 8.

[CLAassistant]

All committers have signed the CLA.