chore(package): update eslint-plugin-jsx-a11y to version 6.1.1

Closes #24

Author: greenkeeper[bot]

package.json

@@ -25,7 +25,7 @@
   "main": "index.js",
   "devDependencies": {
     "eslint-config-airbnb": "^16.1.0",
-    "eslint-plugin-jsx-a11y": "^5.1.1"
+    "eslint-plugin-jsx-a11y": "^6.1.1"
   },
   "repository": {
     "type": "git",