[Vendor] Bumpup hcsshim version from v0.8.25 to v0.8.26.

vendor/github.com/Microsoft/hcsshim/hcn/hcnerrors.go

@@ -10,6 +10,7 @@ import (
 	"github.com/Microsoft/hcsshim/internal/hcserror"
 	"github.com/Microsoft/hcsshim/internal/interop"
 	"github.com/sirupsen/logrus"
+	"golang.org/x/sys/windows"
 )
 
 var (
@@ -50,6 +51,7 @@ type ErrorCode uint32
 const (
 	ERROR_NOT_FOUND                     = 0x490
 	HCN_E_PORT_ALREADY_EXISTS ErrorCode = 0x803b0013
+	HCN_E_NOTIMPL             ErrorCode = ErrorCode(windows.E_NOTIMPL)
 )
 
 type HcnError struct {
@@ -77,6 +79,10 @@ func IsPortAlreadyExistsError(err error) bool {
 	return CheckErrorWithCode(err, HCN_E_PORT_ALREADY_EXISTS)
 }
 
+func IsNotImplemented(err error) bool {
+	return CheckErrorWithCode(err, HCN_E_NOTIMPL)
+}
+
 func new(hr error, title string, rest string) error {
 	err := &HcnError{}
 	hcsError := hcserror.New(hr, title, rest)