Request for clarification regarding OSCAR Schema v2 (schema-v2.md)

[chris-ha458]

OSCAR Schema v2 found in docs/schema/schema-v2.md
shows json files compressed into gz format.
my understanding is that OSCAR-2301 has moved to zstd format with the extension .zst

I think this should change to show files with .zst format or to merely mention that these files are compressed and
that this is just an example choice for compression.