chore(deps): update dependency prettier to v2

Author: renovate-bot

package-lock.json

@@ -84,7 +84,7 @@
     "npm-run-all": "^4.1.5",
     "nyc": "^15.0.1",
     "power-assert": "^1.6.1",
-    "prettier": "^1.19.1",
+    "prettier": "^2.0.4",
     "rimraf": "^3.0.2",
     "standard-version": "^7.1.0",
     "typescript": "^3.8.3"