Bump to v4.12.0.

_mapCacheDelete.js

@@ -0,0 +1,17 @@
+define(['./_getMapData'], function(getMapData) {
+
+  /**
+   * Removes `key` and its value from the map.
+   *
+   * @private
+   * @name delete
+   * @memberOf MapCache
+   * @param {string} key The key of the value to remove.
+   * @returns {boolean} Returns `true` if the entry was removed, else `false`.
+   */
+  function mapCacheDelete(key) {
+    return getMapData(this, key)['delete'](key);
+  }
+
+  return mapCacheDelete;
+});