How to specify the NetCDF format version in the NCAS-GENERAL standard?

[agstephens]

@barbarabrooks and @gapintheclouds:

Following the comment yesterday about the NetCDF version used in our files: here is a proposal about how we could do it.

• [x] Decide which format we mandate:
  • Defined here: https://sites.google.com/ncas.ac.uk/ncasobservations/home/data-project/ncas-data-standards/ncas-amof
  • Format: NetCDF4 Classic
• [ ] Add a new check to the compliance-check-lib library in this module: https://github.com/cedadev/compliance-check-lib/blob/main/checklib/register/format_checks_register.py
  • Call it: NCFileFormatVersionCheck
  • It will test for the dataset.file_format attribute
• [ ] Add this as a check in the general rules set up in the amf-check-writer code here: https://github.com/ncasuk/amf-check-writer/blob/main/amf_check_writer/yaml_check.py#L95-L105
• [ ] Add tests into both packages to check it works.