Convert() should accept the new conversion Context value

Allows Convert() to reuse the same conversions as ConvertToVersion
without being overly coupled to the version.

pkg/api/serialization_proto_test.go

@@ -106,7 +106,7 @@ func BenchmarkEncodeCodecFromInternalProtobuf(b *testing.B) {
 	width := len(items)
 	encodable := make([]api.Pod, width)
 	for i := range items {
-		if err := api.Scheme.Convert(&items[i], &encodable[i]); err != nil {
+		if err := api.Scheme.Convert(&items[i], &encodable[i], nil); err != nil {
 			b.Fatal(err)
 		}
 	}