maven-javadoc-plugin 升级到 3.1.1

    Release Notes - Maven Javadoc Plugin - Version 3.1.1

Bug

[MJAVADOC-539] - Upgrading plugin from 3.0.0 to 3.0.1 and 3.1.0 breaks certain external javadoc links
[MJAVADOC-589] - JDK 12 Classes Not Automatically Linked
[MJAVADOC-591] - javadoc fails with maven.compiler.release=8 and Automatic-Module-Name
[MJAVADOC-599] - javadoc:aggregate-jar does not create the jar when executed as build plugin
[MJAVADOC-608] - Unable to run javadoc:aggregate on multi-module projects with one or more pom modules when using Java modules (jigsaw).