sync pysnirf to support the latest snirf spec

[fangq]

hi @bbfrederick, just to let you know David, Jay, Ted and I had finally made an almost final version of the SNIRF format (I believe David is going to make an announcement soon), and there have been some naming changes as well as format changes.

if you are interested in updating pysnirf to use the latest spec, feel free to let me know if I can be any help. I've already linked your repository (fNIRS/pysnirf, happy to change to your personal dev branch if you prefer) to the snirf main repo under lib/python.

[BA-KS]

@bbfrederick any update on this issue?
I used a data set from openfnirs archive and used pysnirf to read the data. It threw format_version error metadata tags missing but all of them were present. I realized that specification has changed.