MAINT: use new_taxdump in fetch-ncbi-taxonomy?

[Sann5]

• The fetch-ncbi-taxonomy action downloads the taxdump data from the NCBI Taxonomy FTP server so it can be used by the build-sutom-diamond-db action to create a Diamond database.
• This taxdump data is the same that is used in the Diamond tutorial, however the NCBI Taxonomy FTP server also has what they called new_taxdump, what we believe is an updated version of the "old" taxdump data.
• We would like to explore replacing the old taxdump data with the new, taking care that it is compatible with the downstream Diamond database creation.

Relevant documentation: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7408187/