Update es5.d.ts

src/lib/es5.d.ts

@@ -216,7 +216,7 @@ interface ObjectConstructor {
       * Returns the names of the enumerable properties and methods of an object.
       * @param o Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.
       */
-    keys(o: any): string[];
+    keys(o: {}): string[];
 }
 
 /**