Use a more recent stable version of Rust.

jdm · web-flow · commit eef5684106aa · 2018-09-21T09:12:59.000-04:00
diff --git a/.travis.yml b/.travis.yml
@@ -3,7 +3,7 @@ rust:
   - nightly
   - beta
   - stable
-  - 1.25.0
+  - 1.26.0
 sudo: 9000
 dist: trusty
 os:
