Update dependency eslint to v7

Author: renovate-bot

package.json

@@ -71,7 +71,7 @@
     "cssnano": "4.1.10",
     "enzyme": "3.11.0",
     "enzyme-adapter-react-16": "1.15.2",
-    "eslint": "6.8.0",
+    "eslint": "7.0.0",
     "eslint-config-prettier": "6.11.0",
     "eslint-plugin-import": "2.20.2",
     "eslint-plugin-react": "7.19.0",