Update nyan.plugin.zsh

plugins/nyan/nyan.plugin.zsh

@@ -1,5 +1,5 @@
 if [[ -x `which nc` ]]; then
-  alias nyan='nc -v nyan.howes.net.nz 23' # nyan cat
+  alias nyan='nc -v nyancat.dakko.us 23' # nyan cat
 fi