vendor: update buildkit to master@9624ab4

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

vendor/github.com/docker/cli/opts/opts.go

@@ -230,7 +230,7 @@ type ValidatorFctListType func(val string) ([]string, error)
 
 // ValidateIPAddress validates an Ip address.
 func ValidateIPAddress(val string) (string, error) {
-	var ip = net.ParseIP(strings.TrimSpace(val))
+	ip := net.ParseIP(strings.TrimSpace(val))
 	if ip != nil {
 		return ip.String(), nil
 	}