modkit find-motifs won't accept gzipped reference genome

[granek]

modkit find-motifs fails if the reference genome is gzipped (see example error message below). This is inconvenient, inconsistent with dorado, which accepts a gzipped reference genome, and not clear from the documentation.

> loading references from "GCF_000840245.1_ViralProj14204_genomic.fna.gz"
> 0 sequences read                                                                                                                                                                                                     
> failed to load 1 record(s)
> Error! failed to read any reference sequences

[ArtRand]

Hello @granek,

The build available here should. I need to get this into a release very soon.