chore(deps): bump github.com/moby/buildkit from 0.12.5 to 0.13.0 (#3072)

Bumps [github.com/moby/buildkit](https://github.com/moby/buildkit) from 0.12.5 to 0.13.0.
- [Release notes](https://github.com/moby/buildkit/releases)
- [Commits](https://github.com/moby/buildkit/compare/v0.12.5...v0.13.0)

---
updated-dependencies:
- dependency-name: github.com/moby/buildkit
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

vendor/github.com/opencontainers/image-spec/specs-go/v1/annotations.go

@@ -59,10 +59,4 @@ const (
 
 	// AnnotationBaseImageName is the annotation key for the image reference of the image's base image.
 	AnnotationBaseImageName = "org.opencontainers.image.base.name"
-
-	// AnnotationArtifactCreated is the annotation key for the date and time on which the artifact was built, conforming to RFC 3339.
-	AnnotationArtifactCreated = "org.opencontainers.artifact.created"
-
-	// AnnotationArtifactDescription is the annotation key for the human readable description for the artifact.
-	AnnotationArtifactDescription = "org.opencontainers.artifact.description"
 )

vendor/github.com/opencontainers/image-spec/specs-go/v1/descriptor.go

@@ -21,7 +21,7 @@ import digest "github.com/opencontainers/go-digest"
 // when marshalled to JSON.
 type Descriptor struct {
 	// MediaType is the media type of the object this schema refers to.
-	MediaType string `json:"mediaType,omitempty"`
+	MediaType string `json:"mediaType"`
 
 	// Digest is the digest of the targeted content.
 	Digest digest.Digest `json:"digest"`
@@ -52,7 +52,7 @@ type Descriptor struct {
 // Platform describes the platform which the image in the manifest runs on.
 type Platform struct {
 	// Architecture field specifies the CPU architecture, for example
-	// `amd64` or `ppc64`.
+	// `amd64` or `ppc64le`.
 	Architecture string `json:"architecture"`
 
 	// OS specifies the operating system, for example `linux` or `windows`.
@@ -70,3 +70,11 @@ type Platform struct {
 	// example `v7` to specify ARMv7 when architecture is `arm`.
 	Variant string `json:"variant,omitempty"`
 }
+
+// DescriptorEmptyJSON is the descriptor of a blob with content of `{}`.
+var DescriptorEmptyJSON = Descriptor{
+	MediaType: MediaTypeEmptyJSON,
+	Digest:    `sha256:44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a`,
+	Size:      2,
+	Data:      []byte(`{}`),
+}

vendor/github.com/opencontainers/image-spec/specs-go/v1/index.go

@@ -24,9 +24,15 @@ type Index struct {
 	// MediaType specifies the type of this document data structure e.g. `application/vnd.oci.image.index.v1+json`
 	MediaType string `json:"mediaType,omitempty"`
 
+	// ArtifactType specifies the IANA media type of artifact when the manifest is used for an artifact.
+	ArtifactType string `json:"artifactType,omitempty"`
+
 	// Manifests references platform specific manifests.
 	Manifests []Descriptor `json:"manifests"`
 
+	// Subject is an optional link from the image manifest to another manifest forming an association between the image manifest and the other manifest.
+	Subject *Descriptor `json:"subject,omitempty"`
+
 	// Annotations contains arbitrary metadata for the image index.
 	Annotations map[string]string `json:"annotations,omitempty"`
 }

vendor/github.com/opencontainers/image-spec/specs-go/v1/layout.go

@@ -15,10 +15,14 @@
 package v1
 
 const (
-	// ImageLayoutFile is the file name of oci image layout file
+	// ImageLayoutFile is the file name containing ImageLayout in an OCI Image Layout
 	ImageLayoutFile = "oci-layout"
 	// ImageLayoutVersion is the version of ImageLayout
 	ImageLayoutVersion = "1.0.0"
+	// ImageIndexFile is the file name of the entry point for references and descriptors in an OCI Image Layout
+	ImageIndexFile = "index.json"
+	// ImageBlobsDir is the directory name containing content addressable blobs in an OCI Image Layout
+	ImageBlobsDir = "blobs"
 )
 
 // ImageLayout is the structure in the "oci-layout" file, found in the root

vendor/github.com/opencontainers/image-spec/specs-go/v1/manifest.go

@@ -39,11 +39,3 @@ type Manifest struct {
 	// Annotations contains arbitrary metadata for the image manifest.
 	Annotations map[string]string `json:"annotations,omitempty"`
 }
-
-// ScratchDescriptor is the descriptor of a blob with content of `{}`.
-var ScratchDescriptor = Descriptor{
-	MediaType: MediaTypeScratch,
-	Digest:    `sha256:44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a`,
-	Size:      2,
-	Data:      []byte(`{}`),
-}

vendor/github.com/opencontainers/image-spec/specs-go/v1/mediatype.go

@@ -70,6 +70,6 @@ const (
 	// MediaTypeImageConfig specifies the media type for the image configuration.
 	MediaTypeImageConfig = "application/vnd.oci.image.config.v1+json"
 
-	// MediaTypeScratch specifies the media type for an unused blob containing the value `{}`
-	MediaTypeScratch = "application/vnd.oci.scratch.v1+json"
+	// MediaTypeEmptyJSON specifies the media type for an unused blob containing the value `{}`
+	MediaTypeEmptyJSON = "application/vnd.oci.empty.v1+json"
 )

vendor/github.com/opencontainers/image-spec/specs-go/version.go

@@ -25,7 +25,7 @@ const (
 	VersionPatch = 0
 
 	// VersionDev indicates development branch. Releases will be empty string.
-	VersionDev = "-rc.3"
+	VersionDev = "-rc.5"
 )
 
 // Version is the specification version that the package types support.