chore(deps-dev): bump eslint from 3.19.0 to 6.6.0

Bumps [eslint](https://github.com/eslint/eslint) from 3.19.0 to 6.6.0.
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/master/CHANGELOG.md)
- [Commits](eslint/eslint@v3.19.0...v6.6.0)

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

package.json

@@ -26,7 +26,7 @@
     "babel-preset-es2015": "^6.3.13",
     "babel-register": "^6.4.3",
     "coveralls": "^2.11.6",
-    "eslint": "^3.9.0",
+    "eslint": "^6.6.0",
     "eslint-config-dustinspecker": "^1.1.0",
     "eslint-plugin-no-use-extend-native": "^0.3.4",
     "eslint-plugin-xo": "^1.0.0",