Upgrade python-scraperlib to 3.x, including CLI support for description / long_description flags

[benoit74]

See openzim/overview#21

[rgaudin]

Not a valid requests, zimit had those since 1.4.0 (3w old)

[benoit74]

@rgaudin I'm sorry, but I struggle to find how you set a long description with zimit

[rgaudin]

You're right --long-description is not passed to warc2zim. It's an easy fix. Do you want to do it? We'd need to update the ZF offliner as well so it's available everywhere

[benoit74]

I won't do it now, but I intend to do it at some point. Feel free to do it now if you want.

[rgaudin]

Fixed