Metadata modification for updated filenames doesn't cover `B0Field` fields

[tsalo]

In addition to IntendedFor, which CuBIDS does cover, BIDS has B0Fieldentifier and B0FieldSource (and potentially other bids:uri or path-format fields pointing to files in the dataset) that it doesn't modify. See below for the section that explicitly covers IntendedFor.

https://github.com/PennLINC/CuBIDS/blob/b8f5d47d64ba86506880a58249929ab13000c54a/cubids/cubids.py#L494-L513