chore(deps-dev): update eslint requirement from 6.3.0 to 6.4.0

Updates the requirements on [eslint](https://github.com/eslint/eslint) to permit the latest version.
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/master/CHANGELOG.md)
- [Commits](eslint/eslint@v6.3.0...v6.4.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

package.json

@@ -54,7 +54,7 @@
     "babel-jest": "24.9.0",
     "babel-polyfill": "6.26.0",
     "cz-conventional-changelog-emoji": "0.1.0",
-    "eslint": "6.3.0",
+    "eslint": "6.4.0",
     "husky": "3.0.5",
     "jest": "24.9.0",
     "lint-staged": "9.2.5",