Automatically upload docker image

[LucaMarconato]

scvi-tools uploads a docker image at each release: https://github.com/scverse/scvi-tools/tree/main/.github/workflows

In spatialdata we have a different approach: we run a job everyday that checks if any spatialdata-xx package changed version, and in that case it builds and uploads a joint docker image: https://github.com/scverse/spatialdata/blob/main/.github/workflows/build_image.yml.

The various docker images can be accessed here: https://github.com/orgs/scverse/packages.

I suggest we add a similar job also for this repo. Only risk is to create a large number of images, but we can prune things every now and then if we hit some quota limits.

[LucaMarconato]

Same comment as here: #13 (comment).

[LucaMarconato]

Also, we don't want to duplicate efforts with https://github.com/scleestacks/scleestacks, but the versions listed there do not seem up-to-date.