zulip
It would be great if one could send attachments such as images
Hmm, yeah, that could be nice. Do you have a suggestion of how you'd want the interface to work for that?
@timabbott, i thought a bit about it. One option could be to allow markdown in the content field of github-actions-zulip, similar to how zulip itself references attachments. The URL could then be an absolute/relative filesystem URL. However, this might open some security holes, so you probably want this to be opt-in with a flag. Alternatively, the content string could allow placeholders for filenames "This is a message [File](fileA)", and an extra files field would then be used to map placeholders to local filenames.
I just looked into this. Here some pointers in case anyone finds time to implement this. They key API is upload-file, which would need to be exposed in https://github.com/zulip/zulip-js, which seems to lack support for this. Afterwards, this feature needs to be piped through to this GitHub action.