chore(package): update prettier to version 1.19.1

Closes #67

Author: greenkeeper[bot]

demo/package.json

@@ -67,7 +67,7 @@
     "jest": "24.3.1",
     "jest-preset-angular": "7.0.1",
     "lodash": "4.17.11",
-    "prettier": "1.16.4",
+    "prettier": "1.19.1",
     "protractor": "~5.4.2",
     "reflect-metadata": "~0.1.10",
     "run-sequence": "2.2.1",