Update dependency eslint to v7

Author: renovate-bot

package.json

@@ -36,7 +36,7 @@
         "@typescript-eslint/parser": "2.30.0",
         "@types/node": "13.13.4",
         "codecov": "3.6.5",
-        "eslint": "6.8.0",
+        "eslint": "7.4.0",
         "eslint-plugin-import": "2.20.2",
         "eslint-plugin-prefer-arrow": "1.2.1",
         "eslint-config-prettier": "6.11.0",