Bump to v3.0.0.

internal/mapHas.js

@@ -0,0 +1,20 @@
+/** Used for native method references. */
+var objectProto = Object.prototype;
+
+/** Used to check objects for own properties. */
+var hasOwnProperty = objectProto.hasOwnProperty;
+
+/**
+ * Checks if a cached value for `key` exists.
+ *
+ * @private
+ * @name has
+ * @memberOf _.memoize.Cache
+ * @param {string} key The key of the entry to check.
+ * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
+ */
+function mapHas(key) {
+  return key != '__proto__' && hasOwnProperty.call(this.__data__, key);
+}
+
+export default mapHas;