Awaitility 4.0.0-rc1 is released

[Johan Haleby]

This release requires Java 8 and above. Please try it out and provide feedback/bugs. Changes are:

* Upgraded Kotlin extension to use Kotlin 1.3.41 (instead of 1.3.11)
* Better handling of InterruptedException using code from Guava (Uninterruptibles#sleepUninterruptibly) (issue 134)
* Added org.awaitility.core.ConditionEvaluationLogger#conditionEvaluationLogger() methods. This is only useful for syntactic sugar to avoid having to write the "new" keyword in Java when using a ConditionEvaluationLogger. For example:
    await().with().conditionEvaluationListener(conditionEvaluationLogger()). ..
* Awaitility now requires Java 8+ (i.e. support for Java 6 and Java 7 is dropped).
* Hamcrest is update from version 1.3 to 2.1.
* Awaitility now requires Java 8
* Scala version is updated from 2.11.8 to 2.13.0
* Upgraded Groovy from 2.4.11 to 2.5.7
* Removed the awaitility-proxy module since it's no longer required when using Java 8+.
* Removed the org.awaitility.core.Predicate interface, use java.util.function.Predicate instead.
* Removed the org.awaitility.core.BiFunction interface, use java.util.function.BiFunction instead.
* Removed the org.awaitility.core.Supplier interface, use java.util.function.Supplier instead.
* Replaced IllegalStateException with IllegalArgumentException when constructing erroneous ConditionSettings
* Removed org.awaitility.Duration, use java.time.Duration instead. Constants such as ONE_SECOND, TWO_HUNDRED_MILLISECONDS have been moved to org.awaitility.Durations.

Enjoy!