lib: Fix nishimiya's IP

lib/network.nix

@@ -3,7 +3,7 @@ rec {
 
   # A collection of IP addresses for various uses
   miku = "${network-base}.38";
-  nishimiya = "${network-base}.21";
+  nishimiya = "${network-base}.59";
   tamaki = "${network-base}.27";
   mashu = "${network-base}.54";
 }