vendor: update buildkit to 539be170

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

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

@@ -292,6 +292,17 @@ func (c *Client) solve(ctx context.Context, def *llb.Definition, runGateway runG
 					Timestamp: v.Timestamp,
 				})
 			}
+			for _, v := range resp.Warnings {
+				s.Warnings = append(s.Warnings, &VertexWarning{
+					Vertex:     v.Vertex,
+					Level:      int(v.Level),
+					Short:      v.Short,
+					Detail:     v.Detail,
+					URL:        v.Url,
+					SourceInfo: v.Info,
+					Range:      v.Ranges,
+				})
+			}
 			if statusChan != nil {
 				statusChan <- &s
 			}