fix(build): skip errorprone publishing on JDK 8

[halibobo1205]

What does this PR do?

Disables the errorprone module's Maven publish tasks on JDK 8, matching the existing compile and jar skips:

// No jar is produced, so the root maven-publish setup must not try to publish one
tasks.withType(AbstractPublishToMaven).configureEach { enabled = false }

This is intentionally limited to a two-line change in errorprone/build.gradle.

Why are these changes required?

errorprone is a compile-time-only module. Its error_prone_check_api and error_prone_core 2.42.0 dependencies contain Java 17 bytecode, which JDK 8 cannot read. The module therefore already disables its JavaCompile and Jar tasks on JDK 8, so no jar is produced.

However, the root build.gradle applies maven-publish to every subproject and publishes components.java. As a result, publishToMavenLocal still tries to publish the missing errorprone jar:

> Task :errorprone:jar SKIPPED
...
> Task :errorprone:publishMavenJavaPublicationToMavenLocal FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':errorprone:publishMavenJavaPublicationToMavenLocal'.
> Failed to publish publication 'mavenJava' to repository 'mavenLocal'
   > Artifact errorprone-1.0.0.jar wasn't produced by this build.

The original failure is visible in the JitPack build log for GreatVoyage-v4.8.2.

The architecture gate requires JDK 8 on x86_64, so publishToMavenLocal consistently fails on that architecture. This also breaks the installation command in jitpack.yml. The publish task is unaffected, because no publishing repository is configured and it therefore resolves to an empty lifecycle task.

The failure only affects Maven publishing. Regular JDK 8 builds remain unaffected because no module applies the Error Prone plugin or depends on this jar in that configuration. The JDK 17 path is unchanged and continues to compile, package, and publish the module normally.

generatePomFileForMavenJavaPublication and generateMetadataFileForMavenJavaPublication are not AbstractPublishToMaven tasks, so they still run on JDK 8. They only write files into the build directory, and nothing is installed once publishMavenJavaPublicationToMavenLocal is disabled.

This PR has been tested by:

• Manual Testing

No unit test is added because this is a Gradle build-script configuration change with no Java code involved.

Check	Result
publishMavenJavaPublicationToMavenLocal with JDK 8 on x86_64	SKIPPED; build succeeds
Same command with the change reverted	Fails with Artifact errorprone-1.0.0.jar wasn't produced by this build.
errorprone task states on JDK 17	compileJava, jar, and the publish task remain enabled
Full jitpack.yml installation command on JDK 17	Build succeeds and all modules are published
./gradlew lint	Passes

Follow up

• The existing guard uses isJava11Compatible() and its comment says JDK 11+, while Error Prone 2.42.0 actually requires JDK 17. This is currently masked by the architecture gate, which permits only JDK 8 on x86_64 or JDK 17 on arm64. The guard and comment should be aligned when the JDK 21 work relaxes that gate.
• Adding a JDK 8/x86_64 CI job that runs the installation command from jitpack.yml would catch similar publishing regressions. No current workflow runs publishToMavenLocal.

Extra details

The regression was introduced in #6698, which added the JDK 8 compile and jar skips but did not disable the corresponding publish tasks.