Update dependency prettier to v1.19.1

Author: renovate-bot

package-lock.json

@@ -45,7 +45,7 @@
     "codecov": "3.5.0",
     "jest": "24.8.0",
     "nyc": "14.1.1",
-    "prettier": "1.18.0",
+    "prettier": "1.19.1",
     "ts-jest": "24.0.2",
     "tslint": "5.17.0",
     "tslint-config-prettier": "1.18.0",