Update dependency prettier to v2.8.4

Author: renovate[bot]

package-lock.json

@@ -26,7 +26,7 @@
     "stylelint-config-standard": "^20.0.0"
   },
   "devDependencies": {
-    "prettier": "2.1.1",
+    "prettier": "2.8.4",
     "eslint-loader": "4.0.2",
     "eslint": "7.8.1",
     "eslint-plugin-react": "^7.20.5",