Travis: "openjdk-ea" now means Java 13, so add Java 12 to JDKs to build on. (closes #396)
Travis: "openjdk-ea" now means Java 13, so add Java 12 to JDKs to build on. (closes #396)

MarkDacek/commons-lang,britter/commons-lang,apache/commons-lang,MarkDacek/commons-lang,MarkDacek/commons-lang,apache/commons-lang,britter/commons-lang,britter/commons-lang,apache/commons-lang