It would be sensible to add a reference to this from the version-support page, but Go protobuf is in a unique state compared to all other supported languages, see the "Compatibility" section here:
tl;dr unlike other supported languages the versions of Go Protobuf are not coupled with protoc version. To date it has managed to stay on 1.x with a rolling codegen<->runtime compatibility window, but does reserve the right to do a breaking change at some future date (info about that on the above link), but none are currently planned.