Update dependency prettier to v1.19.1 (#207)

Update dependency prettier to v1.19.1

Author: ghengeveld

package.json

@@ -63,7 +63,7 @@
     "lerna": "3.18.4",
     "now": "16.4.4",
     "npm-run-all": "4.1.5",
-    "prettier": "1.18.2",
+    "prettier": "1.19.1",
     "prop-types": "15.7.2",
     "react": "16.11.0",
     "react-async": "9.0.0",