Include new properties in manifest and descriptor

- Include ArtifactType property in Descriptor struct
- Include Refers property in Manifest struct
- Update copyright dates

Signed-off-by: nisha <[email protected]>

Author: nishakm

specs-go/v1/descriptor.go

@@ -1,4 +1,4 @@
-// Copyright 2016 The Linux Foundation
+// Copyright 2016-2022 The Linux Foundation
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -29,6 +29,9 @@ type Descriptor struct {
 	// Size specifies the size in bytes of the blob.
 	Size int64 `json:"size"`
 
+	// ArtifactType is the type of artifact this schema refers to.
+	ArtifactType string `json:"artifactType,omitempty"`
+
 	// URLs specifies a list of URLs from which this object MAY be downloaded
 	URLs []string `json:"urls,omitempty"`
 

specs-go/v1/manifest.go

@@ -1,4 +1,4 @@
-// Copyright 2016 The Linux Foundation
+// Copyright 2016-2022 The Linux Foundation
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -30,6 +30,9 @@ type Manifest struct {
 	// Layers is an indexed list of layers referenced by the manifest.
 	Layers []Descriptor `json:"layers"`
 
+	// Refers is an optional link to any existing manifest within the repository.
+	Refers *Descriptor `json:"refers,omitempty"`
+
 	// Annotations contains arbitrary metadata for the image manifest.
 	Annotations map[string]string `json:"annotations,omitempty"`
 }