fix(package): update emotion to version 10.0.4

Closes #30

Author: greenkeeper[bot]

package.json

@@ -3,7 +3,7 @@
   "version": "0.1.0",
   "private": true,
   "dependencies": {
-    "emotion": "^9.1.3",
+    "emotion": "^10.0.4",
     "final-form": "^4.2.0",
     "glamor": "^2.20.40",
     "govuk-colours": "^1.0.3",