Travis: build using openjdk8

ctrueden · ctrueden · commit 2c89a2e6ae87 · 2019-04-30T17:04:48.000-05:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,5 +1,5 @@
 language: java
-jdk: oraclejdk8
+jdk: openjdk8
 branches:
   only:
   - master
