[Snowflake] Update the standalone instructions
From tpo/anti-censorship/pluggable-transports/snowflake#40125 (closed)
If I may I'd point out that the NAT behaviour tool page linked at https://community.torproject.org/relay/setup/snowflake/standalone/ needs updating as well. Currently the syntax uses 'go get' which is deprecated in favour of 'go install'. I only had success with "go install github.com/pion/stun/cmd/stun-nat-behaviour@latest".