changes to support any mediatype for layers on download

Signed-off-by: LochanRn <rajanaga_ra@srmuniv.edu.in>
(cherry picked from commit 9e29f1619b)

internal/experimental/registry/client.go

@@ -224,7 +224,7 @@ func (c *Client) Pull(ref string, options ...PullOption) (*PullResult, error) {
 	minNumDescriptors := 1 // 1 for the config
 	if operation.withChart {
 		minNumDescriptors++
-		allowedMediaTypes = append(allowedMediaTypes, ChartLayerMediaType)
+		allowedMediaTypes = append(allowedMediaTypes, ChartLayerMediaType, LegacyChartLayerMediaType)
 	}
 	if operation.withProv {
 		if !operation.ignoreMissingProv {
@@ -256,6 +256,9 @@ func (c *Client) Pull(ref string, options ...PullOption) (*PullResult, error) {
 			chartDescriptor = &d
 		case ProvLayerMediaType:
 			provDescriptor = &d
+		case LegacyChartLayerMediaType:
+			chartDescriptor = &d
+			fmt.Fprintf(c.out, "Warning: chart media type %s is deprecated\n", LegacyChartLayerMediaType)
 		}
 	}
 	if configDescriptor == nil {

internal/experimental/registry/constants.go

@@ -31,4 +31,7 @@ const (
 
 	// ProvLayerMediaType is the reserved media type for Helm chart provenance files
 	ProvLayerMediaType = "application/vnd.cncf.helm.chart.provenance.v1.prov"
+
+	// LegacyChartLayerMediaType is the legacy reserved media type for Helm chart package content.
+	LegacyChartLayerMediaType = "application/tar+gzip"
 )