try better build matrix

Author: mraerino

.travis.yml

@@ -1,28 +1,31 @@
-language: go
-node_js: '12'
-go: '1.13'
 dist: bionic
 jobs:
   include:
     - language: go
+      go: "1.13"
       os: windows
       install:
         - choco install make
         - make deps
       script: make test
     - language: go
+      go: "1.13"
       os: osx
       install: make deps
       script: make test
     - language: go
+      go: "1.13"
       os: linux
       install: make deps
       script: make test
     - language: node_js
+      node_js: "12"
       os: windows
     - language: node_js
+      node_js: "12"
       os: osx
     - language: node_js
+      node_js: "12"
       os: linux
 cache: npm
 notifications: