update vendor README.md

vendor/README.md

@@ -109,3 +109,12 @@ See also LICENSE.txt in the `glfw` directory itself.
 `portmidi_s.lib` is available under PortMidi's [MIT](https://sourceforge.net/projects/portmedia/) license.
 
 See also LICENSE.txt in the `portmidi` directory itself.
+
+
+## ENet
+
+[ENet](http://enet.bespin.org/) Reliable UDP networking library.
+
+`enet.lib` and `enet64.lib` are available under ENet's [zlib/libpng](http://enet.bespin.org/License.html) license.
+
+See also LICENSE in the `ENet` directory iself.