Add OpenJDK 12 to Travis builds. Also 13-EA.

Gary Gregory · Gary Gregory · commit 93630178dd60 · 2019-04-16T09:11:38.000-04:00
diff --git a/.travis.yml b/.travis.yml
@@ -23,6 +23,8 @@ jdk:
   - openjdk8
   - openjdk10
   - openjdk11
+  - openjdk12
+  - openjdk-ea  
 
 script:
   - mvn
