assert SetupConnection min_version(?)

[lucasbalieiro]

should we implement the same check from stratum-mining/sv2-apps#694 at the low-level crate level, returning an error if the version doesn't match the spec?

[plebhash]

yeah makes sense

[plebhash]

yeah makes sense

unless it's too complex to implement, in which case maybe just enforce at the app layer?