Update .travis.yml

ankadada · ankadada · commit c1867c29cce9 · 2019-08-01T10:51:11.000+08:00
diff --git a/.travis.yml b/.travis.yml
@@ -7,6 +7,8 @@ php:
   - 5.6
   - 7.0
 
+dist: trusty
+
 before_script:
   - export QINIU_TEST_ENV="travis"
   - travis_retry composer self-update
