Creates a spreadsheet with the format required for a PSE from a list of taxa.
createPSE(taxa, loc = "proxy_species_equivalency.xlsx")
A list of taxa to include in the PSE file.
An absolute or relative path that indicates where the spreadsheet
should be saved. Also used to specify the name of the file. Default:
the file is saved in the working directory under the name
No return value, called to create a PSE file.