feature request - restrict output fastas extracted to 80bp per line

Hello,

thanks for this nice tool.

I have noticed fastas extracted by this command seem to be in a single fasta line. This is a little excessive when extracting whole chromosomes. Can you please restrict sequence line length to eg 80 chars?

```
# extract odgi to fasta
    odgi paths -f -t $cores -i ${odgi}_pruned.og > x.fasta
```

Thanks.