chore(package): update eslint to version 6.4.0

Closes #29

Author: greenkeeper[bot]

package.json

@@ -8,7 +8,7 @@
     "babel-preset-stage-2": "^6.22.0",
     "babelify": "^7.3.0",
     "browserify": "^14.0.0",
-    "eslint": "^3.18.0",
+    "eslint": "^6.4.0",
     "husky": "^0.14.0",
     "jest": "^19.0.2",
     "lint-staged": "^4.0.0",