Update dependency eslint to v7

Author: renovate-bot

package.json

@@ -52,7 +52,7 @@
   "devDependencies": {
     "@babel/core": "7.7.7",
     "babel-eslint": "10.0.3",
-    "eslint": "6.7.2",
+    "eslint": "7.20.0",
     "eslint-config-prettier": "6.11.0",
     "eslint-plugin-prettier": "3.1.2",
     "eslint-plugin-react": "7.17.0",