Update dependency prettier to v2

Author: renovate-bot

package-lock.json

@@ -31,7 +31,7 @@
     "husky": "4.2.3",
     "jest": "25.1.0",
     "lint-staged": "10.0.8",
-    "prettier": "1.19.1"
+    "prettier": "2.0.5"
   },
   "dependencies": {
     "ethers": "4.0.45"