Fix missing hash in Talos template

This prevented Talos from booting with a `Exec format error` from iPXE

roles/netbootxyz/templates/menu/talos.ipxe.j2

@@ -1,4 +1,4 @@
-!ipxe
+#!ipxe
 
 # Talos
 # https://github.com/siderolabs/talos/releases