Switch from Oracle JDK 8 to Open JDK 8 (#31)

diff --git a/.travis.yml b/.travis.yml
index 6789d48..d52d769 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -17,11 +17,11 @@
 sudo: false

 

 jdk:

+  - openjdk8

   - openjdk11

   - openjdk12

   - openjdk13

   - openjdk-ea

-  - oraclejdk8

 

 script:

   - mvn