travis: upgrade dist version

eagleivg · eagleivg · commit 873b25afbd7d · 2018-08-01T16:21:14.000+03:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,7 +1,7 @@
 language: cpp
 cache: ccache
 sudo: required
-dist: trusty
+dist: xenial
 compiler:
 - g++
 install: export CXX="g++-7"
