.travis.yml in embulk-input-gcs-0.3.1 vs .travis.yml in embulk-input-gcs-0.3.2

@@ -1,6 +1,8 @@
 language: java
 
+dist: trusty
+
 jdk:
   - oraclejdk8
 
 before_install:
   - openssl aes-256-cbc -K $encrypted_407f38382059_key -iv $encrypted_407f38382059_iv