Update dependency prettier to v1.19.1

Author: renovate-bot

package.json

@@ -69,7 +69,7 @@
     "jest": "23.5.0",
     "ncp": "2.0.0",
     "node-fetch": "2.2.0",
-    "prettier": "1.14.2"
+    "prettier": "1.19.1"
   },
   "peerDependencies": {
     "luminol": "*"