vendor: update buildkit to v0.20.0-rc2

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/github.com/moby/buildkit/solver/pb/caps.go

@@ -463,7 +463,7 @@ func init() {
 
 	Caps.Init(apicaps.Cap{
 		ID:      CapRemoteCacheAzBlob,
-		Enabled: false,
+		Enabled: true,
 		Status:  apicaps.CapStatusExperimental,
 	})
 

vendor/github.com/moby/buildkit/solver/result/result.go

@@ -110,6 +110,20 @@ func (r *Result[T]) EachRef(fn func(T) error) (err error) {
 	return err
 }
 
+// IsEmpty returns true if this result does not refer to
+// any references.
+func (r *Result[T]) IsEmpty() bool {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	if len(r.Refs) > 0 {
+		return false
+	}
+
+	var zero T
+	return r.Ref == zero
+}
+
 // EachRef iterates over references in both a and b.
 // a and b are assumed to be of the same size and map their references
 // to the same set of keys

vendor/github.com/moby/buildkit/util/appdefaults/appdefaults_windows.go

@@ -18,7 +18,7 @@ var (
 
 var (
 	UserCNIConfigPath = DefaultCNIConfigPath
-	CDISpecDirs       []string
+	CDISpecDirs       = []string{filepath.Join(os.Getenv("ProgramData"), "buildkitd", "cdi")}
 )
 
 func UserAddress() string {

vendor/github.com/moby/buildkit/util/testutil/workers/dockerd.go

@@ -41,6 +41,7 @@ func InitDockerdWorker() {
 			FeatureSBOM,
 			FeatureSecurityMode,
 			FeatureCNINetwork,
+			FeatureCDI,
 		},
 	})
 	integration.Register(&Moby{
@@ -51,6 +52,7 @@ func InitDockerdWorker() {
 			FeatureSecurityMode,
 			FeatureCNINetwork,
 			FeatureContentCheck,
+			FeatureCDI,
 		},
 	})
 }

vendor/github.com/moby/buildkit/util/testutil/workers/features.go

@@ -31,6 +31,7 @@ const (
 	FeatureSourceDateEpoch      = "source_date_epoch"
 	FeatureCNINetwork           = "cni_network"
 	FeatureContentCheck         = "content_check"
+	FeatureCDI                  = "cdi"
 )
 
 var features = map[string]struct{}{
@@ -58,6 +59,7 @@ var features = map[string]struct{}{
 	FeatureSourceDateEpoch:      {},
 	FeatureCNINetwork:           {},
 	FeatureContentCheck:         {},
+	FeatureCDI:                  {},
 }
 
 func CheckFeatureCompat(t *testing.T, sb integration.Sandbox, reason ...string) {