Don't use hybrid as taxonRank

[peterdesmet]

GBIF will indicate those with rank unknown. That makes sense, you could argue that Berberis x hybrido-gagnepainii J.V. Suringar should have the rank species. I'd therefore suggest to use the correct taxonRank in the Excel file.

We already have a column hybridFormula which should also allow to find the 125 hybrids in the data. For 15 of the 125 it's not populated yet, but once we have that you filter on hybrids again.

GBIF also automatically detect hybridFormula names: https://www.gbif.org/species/search?dataset_key=9ff7d317-609b-4c08-bd86-3bc404b77c42&name_type=HYBRID&issue=RANK_INVALID&advanced=1

To be coordinated with Filip