chore(package): update eslint-config-airbnb-base to version 12.1.0

Closes #33

Author: greenkeeper[bot]

package.json

@@ -47,7 +47,7 @@
     "chalk": "^1.1.3",
     "coveralls": "^2.13.0",
     "eslint": "^3.19.0",
-    "eslint-config-airbnb-base": "^11.1.3",
+    "eslint-config-airbnb-base": "^12.1.0",
     "eslint-plugin-babel": "^4.1.1",
     "eslint-plugin-import": "^2.2.0",
     "flow-bin": "^0.43.1",