vendor: add buildkit

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

vendor/github.com/moby/buildkit/client/graph.go

@@ -0,0 +1,46 @@
+package client
+
+import (
+	"time"
+
+	digest "github.com/opencontainers/go-digest"
+)
+
+type Vertex struct {
+	Digest    digest.Digest
+	Inputs    []digest.Digest
+	Name      string
+	Started   *time.Time
+	Completed *time.Time
+	Cached    bool
+	Error     string
+}
+
+type VertexStatus struct {
+	ID        string
+	Vertex    digest.Digest
+	Name      string
+	Total     int64
+	Current   int64
+	Timestamp time.Time
+	Started   *time.Time
+	Completed *time.Time
+}
+
+type VertexLog struct {
+	Vertex    digest.Digest
+	Stream    int
+	Data      []byte
+	Timestamp time.Time
+}
+
+type SolveStatus struct {
+	Vertexes []*Vertex
+	Statuses []*VertexStatus
+	Logs     []*VertexLog
+}
+
+type SolveResponse struct {
+	// ExporterResponse is also used for CacheExporter
+	ExporterResponse map[string]string
+}