Update go.mod and vendor

vendor/github.com/moby/buildkit/client/client_windows.go

@@ -1,24 +0,0 @@
-package client
-
-import (
-	"net"
-	"strings"
-	"time"
-
-	winio "github.com/Microsoft/go-winio"
-	"github.com/pkg/errors"
-)
-
-func dialer(address string, timeout time.Duration) (net.Conn, error) {
-	addrParts := strings.SplitN(address, "://", 2)
-	if len(addrParts) != 2 {
-		return nil, errors.Errorf("invalid address %s", address)
-	}
-	switch addrParts[0] {
-	case "npipe":
-		address = strings.Replace(addrParts[1], "/", "\\", -1)
-		return winio.DialPipe(address, &timeout)
-	default:
-		return net.DialTimeout(addrParts[0], addrParts[1], timeout)
-	}
-}