Add TestEnvironment.sleep support

[Vitalii Honta]

Currently, the only way to do so is using Java SDK directly:

_     <- ZIO.serviceWith[ZTestWorkflowEnvironment[Any]] { zTestEnv =>
                   zTestEnv.toJava.sleep(java.time.Duration.ofDays(5))
                 }

[Vitalii Honta]

It's done, to be released later