Clojure Tasks: Cleanup Internal properties that should not be marked as Optional

[rpalcolea]

This is to allow compatibility with future versions of Gradle:

Welcome to Gradle 6.3-20200128230909+0000!

Starting a Gradle Daemon (subsequent builds will be faster)

> Configure project :
Inferred project: nebula-clojure-plugin, version: 9.4.0-dev.1.uncommitted+53f227f

> Task :validatePlugins FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':validatePlugins'.
> Plugin validation failed. See https://docs.gradle.org/6.3-20200128230909+0000/userguide/more_about_tasks.html#sec:task_input_output_annotations for more information on how to annotate task properties.
   > Warning: Type 'ClojureCompile': property 'jvmOptions' annotated with @Internal should not be also annotated with @Optional.
   > Warning: Type 'ClojureDoc': property 'jvmOptions' annotated with @Internal should not be also annotated with @Optional.
   > Warning: Type 'ClojureRepl': property 'jvmOptions' annotated with @Internal should not be also annotated with @Optional.
   > Warning: Type 'ClojureRun': property 'jvmOptions' annotated with @Internal should not be also annotated with @Optional.
   > Warning: Type 'ClojureTest': property 'tests' annotated with @Internal should not be also annotated with @Optional.

[coveralls]

Coverage remained the same at 47.17% when pulling 7b99978 on cleanup-tasks-internal-properties into 53f227f on master.