Update vendor d5/tengo

vendor/github.com/d5/tengo/.travis.yml

@@ -0,0 +1,17 @@
+language: go
+
+go:
+  - 1.9
+
+install:
+  - go get -u golang.org/x/lint/golint
+
+script:
+  - make test
+
+deploy:
+  - provider: script
+    skip_cleanup: true
+    script: curl -sL https://git.io/goreleaser | bash
+    on:
+      tags: true