Update dependency eslint to v7

Author: renovate-bot

package.json

@@ -32,7 +32,7 @@
         "codecov": "3.7.0",
         "@typescript-eslint/eslint-plugin": "3.1.0",
         "@typescript-eslint/parser": "3.1.0",
-        "eslint": "6.8.0",
+        "eslint": "7.3.1",
         "eslint-config-prettier": "6.11.0",
         "eslint-config-standard-with-typescript": "18.0.2",
         "eslint-plugin-import": "2.20.2",