use kyoh86/richgo to provide colored test outputs

Author: umarcor

.travis.yml

@@ -22,8 +22,9 @@ before_install:
   - mkdir -p bin
   - curl -Lso bin/shellcheck https://github.com/caarlos0/shellcheck-docker/releases/download/v0.6.0/shellcheck
   - chmod +x bin/shellcheck
+  - go get -u github.com/kyoh86/richgo
 script:
-  - PATH=$PATH:$PWD/bin go test -v ./...
+  - PATH=$PATH:$PWD/bin richgo test -v ./...
   - go build
   - if [ -z $NOVET ]; then
       diff -u <(echo -n) <(go vet . 2>&1 | grep -vE 'ExampleCommand|bash_completions.*Fprint');