Merge pull request #12 from xenoamess-fork/patch-2

fix travis-ci script.
diff --git a/.travis.yml b/.travis.yml
index 1f86d9f..afa4630 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -15,11 +15,13 @@
 

 language: java

 sudo: false

-

+dist: trusty

+cache:

+  directories:

+    - $HOME/.m2

 jdk:

-  - openjdk7

-  - oraclejdk7

   - oraclejdk8

-

+  - openjdk8

+  - openjdk11

 after_success:

   - mvn -V --no-transfer-progress clean cobertura:cobertura coveralls:report