Bump to v4.4.0.

difference.js

@@ -18,7 +18,7 @@ define(['./_baseDifference', './_baseFlatten', './isArrayLikeObject', './rest'],
    */
   var difference = rest(function(array, values) {
     return isArrayLikeObject(array)
-      ? baseDifference(array, baseFlatten(values, false, true))
+      ? baseDifference(array, baseFlatten(values, 1, true))
       : [];
   });