Bump eslint from 3.6.1 to 6.6.0

Bumps [eslint](https://github.com/eslint/eslint) from 3.6.1 to 6.6.0.
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/master/CHANGELOG.md)
- [Commits](https://github.com/eslint/eslint/compare/v3.6.1...v6.6.0)
Signed-off-by: Ndependabot[bot] <support@github.com>

package.json

@@ -9,7 +9,7 @@
   "dependencies": {},
   "devDependencies": {
     "browserify": "13.1.0",
-    "eslint": "3.6.1",
+    "eslint": "6.6.0",
     "font-awesome": "4.6.3",
     "preboot": "git+https://github.com/mdo/preboot.git#4aab4edd85f076d50609cbe28e4fe66cc0771701",
     "gitbook-logos": "git+https://github.com/GitbookIO/logos.git#2.0.2",