#!/usr/bin/env bash
node --version
npm --version
yarn --version
yarn install
yarn test

#!/usr/bin/env bash
node --version
npm --version
yarn --version
yarn test

Remove redundant `yarn install` command
Remove redundant `yarn install` command

Travis executes `yarn install` automatically if `yarn.lock` file in the
repository root.

https://blog.travis-ci.com/2016-11-21-travis-ci-now-supports-yarn
https://travis-ci.org/emsk/redmine-now/builds/198339714#L93
