-u parameter should be -U

[till-bornemann]

Hi,

Thanks for providing this nice tool to generate simulated mock communties. While trying out the tool and using one of the code chunks provided at your README

iss generate --ncbi bacteria -u 10 --model MiSeq --output ncbi_reads

I got an error that the -U (instead of the lowercase -u parameter) is required. Changing the -u to -U in the above command fixed the error and now the tools works like a charm. Just wanted to let you know (also since its listed with -u option in the --help of the generate module).

Best,
Till