chore(package): update documentation to version 6.3.1

Closes #10

Author: greenkeeper[bot]

package.json

@@ -22,7 +22,7 @@
     "unist-builder": "^1.0.0"
   },
   "devDependencies": {
-    "documentation": "4.0.0-beta4",
+    "documentation": "6.3.1",
     "jsdoctest": "1.7.0",
     "mocha": "3.2.0",
     "remark": "^7.0.0",