file(ARCHIVE_CREATE): doesn't support format specific COMPRESSION_LEVELs
'file(ARCHIVE_CREATE' supports 'COMPRESSION_LEVEL' from 0 to 9, which is directly translated to an archiver argument. So for zstd compression type it's not possible to set compression level higher than 9. It would be nice to either allow using archiver-specific compression levels or treat the COMPRESSION_LEVEL argument as percentage and scale the resulting compression level accordingly.