build: go 1.24

We were running behind and there were quite some deprecations to update.
This was mostly in the upstream copy/pasta package but seems quite
minimal.

vendor/golang.org/x/crypto/ssh/messages.go

@@ -818,6 +818,8 @@ func decode(packet []byte) (interface{}, error) {
 		return new(userAuthSuccessMsg), nil
 	case msgUserAuthFailure:
 		msg = new(userAuthFailureMsg)
+	case msgUserAuthBanner:
+		msg = new(userAuthBannerMsg)
 	case msgUserAuthPubKeyOk:
 		msg = new(userAuthPubKeyOkMsg)
 	case msgGlobalRequest: