* Mention Custom UDP SG rule for Kcp Transport
Since Kcp Transport is now the default in Mirror, let's update the docs to reflect that the SG needs to have a UDP rule to allow network traffic to reach the server.
* Mention UDP Firewall rule for Kcp Transport
Since Kcp Transport is now the default in Mirror, let's update the docs to reflect that a UDP rule is necessary in order to allow network traffic to reach the server.