fix: add error-prone config for JDK8 (#53)

[jbutler]

Build sometimes fails with JDK 8 because of the error-prone plugin with the following error:

[INFO] Compiling 87 source files to /Users/joebutl/workspace/moquette/broker/target/classes
An exception has occurred in the compiler (1.8.0_282). Please file a bug against the Java compiler via the Java bug reporting page (http://bugreport.java.com) after checking the Bug Database (http://bugs.java.com) for duplicates. Include your program and the following diagnostic in your report. Thank you.
java.lang.RuntimeException: java.lang.NoSuchMethodError: com.sun.tools.javac.util.JavacMessages.add(Lcom/sun/tools/javac/util/JavacMessages$ResourceBundleHelper;)V
	at com.sun.tools.javac.main.Main.compile(Main.java:473)
	at com.sun.tools.javac.api.JavacTaskImpl.doCall(JavacTaskImpl.java:129)
	at com.sun.tools.javac.api.JavacTaskImpl.call(JavacTaskImpl.java:138)
	at org.codehaus.plexus.compiler.javac.JavaxToolsCompiler.compileInProcess(JavaxToolsCompiler.java:126)
	at org.codehaus.plexus.compiler.javac.JavacCompiler.performCompile(JavacCompiler.java:174)
	at org.apache.maven.plugin.compiler.AbstractCompilerMojo.execute(AbstractCompilerMojo.java:1129)
	at org.apache.maven.plugin.compiler.CompilerMojo.execute(CompilerMojo.java:188)
	at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:137)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:210)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:156)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:148)
	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:117)
	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:81)
	at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:56)
	at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
	at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:305)
	at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:192)
	at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:105)
	at org.apache.maven.cli.MavenCli.execute(MavenCli.java:957)
	at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:289)
	at org.apache.maven.cli.MavenCli.main(MavenCli.java:193)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:282)
	at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:225)
	at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:406)
	at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:347)
Caused by: java.lang.NoSuchMethodError: com.sun.tools.javac.util.JavacMessages.add(Lcom/sun/tools/javac/util/JavacMessages$ResourceBundleHelper;)V
	at com.google.errorprone.BaseErrorProneJavaCompiler.setupMessageBundle(BaseErrorProneJavaCompiler.java:200)
	at com.google.errorprone.ErrorProneJavacPlugin.init(ErrorProneJavacPlugin.java:40)
	at com.sun.tools.javac.main.Main.compile(Main.java:470)
	... 28 more
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR :
[INFO] -------------------------------------------------------------
[ERROR] An unknown compilation problem occurred
[INFO] 1 error
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary for Moquette MQTT 0.16-SNAPSHOT:
[INFO]
[INFO] Moquette MQTT ...................................... SUCCESS [  0.106 s]
[INFO] Moquette - broker .................................. FAILURE [  2.334 s]
[INFO] Moquette - distribution ............................ SKIPPED
[INFO] Moquette - Embedded test ........................... SKIPPED
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  2.676 s
[INFO] Finished at: 2021-07-23T16:37:32-06:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.0:compile (default-compile) on project moquette-broker: Compilation failure
[ERROR] An unknown compilation problem occurred

Error-prone maintainers provide this configuration for building with JDK 8 in their installation instructions (link in PR)

[xiaochangbai]

i use jdk11 is ok

[jbutler]

Yes, this change is only needed for JDK8. More recent versions work fine. However, my project requires 8.

This change is copy paste from the errorprone installation instructions - https://errorprone.info/docs/installation