Bump eslint from 4.19.1 to 5.9.0

Bumps [eslint](https://github.com/eslint/eslint) from 4.19.1 to 5.9.0.
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/master/CHANGELOG.md)
- [Commits](eslint/eslint@v4.19.1...v5.9.0)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot-support

package.json

@@ -36,7 +36,7 @@
   "devDependencies": {
     "chai": "^4.2.0",
     "coveralls": "^3.0.2",
-    "eslint": "^4.19.1",
+    "eslint": "^5.9.0",
     "eslint-config-airbnb-base": "^13.0.0",
     "eslint-plugin-import": "^2.2.0",
     "eslint-plugin-mocha": "^5.2.0",