Update dependencies to enable Greenkeeper 🌴 (#3940)

* chore(package): update dependencies

* docs(readme): add Greenkeeper badge

* Fix indent issues with eslint 4.0

see http://eslint.org/docs/user-guide/migrating-to-4.0.0\#-the-indent-rule-is-more-strict

spec/parsers.spec.js

@@ -1,7 +1,7 @@
 import {
-	numberParser,
-	numberOrBoolParser,
-	booleanParser,
+  numberParser,
+  numberOrBoolParser,
+  booleanParser,
 } from '../src/cli/utils/parsers';
 
 describe('parsers', () => {