Upgrade CI to Xenial

benesch · benesch · commit b7125c979a9b · 2019-06-03T17:33:44.000-04:00
This isn't required by anything, but newer distributions tend to boot
faster in Travis.
diff --git a/.travis.yml b/.travis.yml
@@ -1,4 +1,4 @@
-dist: trusty
+dist: xenial
 sudo: required
 cache: cargo
 language: rust
