Fixed security alerts due to documentation.js' use of obsolete disparity package

This was reported to documentation with documentationjs/documentation#1257 and resolved with the merge documentationjs/documentation#1264

Author: robseaman

package.json

@@ -22,7 +22,7 @@
     "@babel/cli": "^7.4.4",
     "@babel/core": "^7.4.4",
     "@babel/preset-env": "^7.4.4",
-    "documentation": "^11.0.0",
+    "documentation": "^12.1.1",
     "eslint": "^5.16.0",
     "eslint-config-airbnb": "^17.1.0",
     "eslint-plugin-import": "^2.17.2",