[BPO] gallery-dl 1.20.0-1 to focal

[Unit 193]

[Impact]

 * This package works with online sites, new releases pick up new sites and fix broken extractors, as such always having the current version available is ideal.

At some point, I'd like to get yt-dlp and gallery-dl on whitelists so I can just backport them to the LTS version, as they both are good to always have the current version since they work with websites, which change often. Specifically YouTube.

[Scope]

 * I intend to backport gallery-dl (1.20.0-1) from Jammy.

 * As per policy, only LTSes are available to backport to, so I'll only be backporting to focal.

[Other Info]

 * This package is also in bullseye-backports, and has autopkgtests.

[Testing]

* focal:
[x] Package builds without modification
[x] gallery-dl installs cleanly and runs

No reverse dependencies

[Mattia Rizzolo (mapreri)]

the "fix broken extractors" bit is normally something that should be handled via SRUs. Is that happening? If not, is there a plan for it, or is this just something that users are living with?

[Mattia Rizzolo (mapreri)]

Actually, forget it, I see this is a new package, so it's fine. diff also looks ok, so I approved it.

(the comment still stands for when jammy will be stable though)