chore(package): update eslint to version 6.4.0

Author: greenkeeper[bot]

package.json

@@ -73,7 +73,7 @@
     "@typescript-eslint/eslint-plugin": "^2.1.0",
     "@typescript-eslint/parser": "^2.0.0",
     "codecov": "^3.5.0",
-    "eslint": "6.3.0",
+    "eslint": "6.4.0",
     "eslint-config-prettier": "^6.0.0",
     "eslint-plugin-react": "^7.14.3",
     "husky": "^3.0.2",