travis-ci: prepare for 1.14 release (#3047)

diff --git a/.travis.yml b/.travis.yml
index cffb782..2ef17c0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,9 +3,9 @@
 dist: bionic
 
 go:
-  - 1.11.x
   - 1.12.x
   - 1.13.x
+  - 1.14.x
   - tip
 
 git: