Remove leftover mentions of TCP in README

[GeckoEidechse]

First of all, I think by now we can drop all mentions of TCP port entirely

Second of all, https://github.com/pg9182/northstar-dedicated#quick-start still makes it seem like TCP is required. The Docker command it shows is

docker run --rm --interactive --pull always --publish 8081:8081/tcp --publish 37015:37015/udp --mount "type=bind,source=/path/to/titanfall2,target=/mnt/titanfall,readonly" --env NS_SERVER_NAME="[YOUR-REGION] Your server name" ghcr.io/pg9182/northstar-dedicated:1-tf2.0.11.0
                                            ^^^^^^^^^^^^^^^^^^^^^^^
                                                   this

[Happyllama25]

Mentioned at auth-port, it does specify it is not required after v1.13+ but version gate has increased since then.

https://github.com/pg9182/northstar-dedicated#environment-variables