now that we have vendor make the travis builds use it

Author: Sean Sain

.travis.yml

@@ -5,9 +5,6 @@ services:
 language: go
 go:
   - "1.13.x"
-  
-env:
-  - GO111MODULE=on
 
 install:
 # This script is used by the Travis build to install a cookie for
@@ -24,3 +21,6 @@ matrix:
   fast_finish: true
   allow_failures:
   - go: tip
+
+env:
+  - GOFLAGS=-mod=vendor GO111MODULE=on