Update prettier to version 2.4.1

Author: depfu[bot]

package.json

@@ -44,7 +44,7 @@
     "mocha": "^8.3.0",
     "nyc": "^15.0.0",
     "offline-github-changelog": "^2.0.0",
-    "prettier": "~2.3.0",
+    "prettier": "~2.4.1",
     "unexpected": "^12.0.0",
     "unexpected-express": "^13.0.1"
   },