Zip postprocessor uses a wrong filename (similar to issue #126)

[jakanaka-eva]

Running gallery-dl --ignore-config --zip 'https://danbooru.donmai.us/pools/14083'
results in a file called
gallery-dl/danbooru/pool/14083/.zip instead of
gallery-dl/danbooru/pool/14083.zip (notice the extra slash).

Bisected to 3284c62.

[mikf]

Well, as before, thank you for the detailed issue description and bisecting the relevant commit.

[Slider-Whistle]

How soon can the release fixing this come out? I was able to fix it for myself by updating to the dev version as described in the readme, but it'd be bad if others ran into this. I was going through the docs thinking something changed.

[mikf]

@Slider-Whistle https://github.com/mikf/gallery-dl/releases/tag/v1.10.3