chore(release): Bump version to 4.2.1 [skip ci]

## [4.2.1](v4.2.0...v4.2.1) (2018-08-15)

### Bug Fixes

* slider default scss allow setting overrides ([6744ee5](6744ee5))

package.json

@@ -1,6 +1,6 @@
 {
   "name": "harmonium",
-  "version": "4.2.0",
+  "version": "4.2.1",
   "description": "An opinionated React component framework for teams that move fast.",
   "repository": {
     "type": "git",