Action to publish docker image

[DCjanus]

Resolve: #93

I have already tested the code of this Pull Request in my own namespace. For details, please see this URL: https://github.com/DCjanus/cargo-machete/pkgs/container/cargo-machete

Since CI is a module that is difficult to debug locally, I have submitted many fragmented commits in this PR, hoping that all my commits will be squashed upon merging.

[bnjbvr]

Hi! Thanks for the contribution, out of curiosity why do you need a Docker image? I think the linked issue has been closed because it was deemed possible to use another step for Github CI workflows, and I'm not sure to see the benefits of using a Docker instance locally — but I might be missing something!

[DCjanus]

For some enterprises with strict network isolation, it may be difficult to directly download a binary from GitHub. However, it is relatively easy to copy a binary from another public docker image because the enterprise can build its own mirror internally.

For example, my Dockerfile.ci could be like this:

FROM debian:stable 

COPY --from=ghcr.io/bnjbvr/cargo-machete:latest /usr/local/bin/cargo-machete /usr/local/bin

[bnjbvr]

Ok, makes sense! I've also received good feedback for a docker image for cargo-machete on the fediverse, so I'm happy taking this change.

in terms of process: what does it entail? IIUC, i would need to set up a new Docker repository at bnjbvr/cargo-machete too. Are there other steps that would be required? (like adding the github bot as a collaborator to the Docker repo, maybe? if so, how does one do that?)

There are a few TODOs in your PR, do you plan to implement them or can/should they be done later, when actually required?

[DCjanus]

If you are only publishing the image to ghcr.io, you don't need to take any action except approval the workflow and merging this PR.

I prefer to implement the TODOs in the future in order to avoid introducing too many changes in one PR.

[DCjanus]

I've also received good feedback for a docker image for cargo-machete on the fediverse

For people who want to gain more idea about this, I'd like to put the link about this feedback here.

https://tutut.delire.party/@bnjbvr/112394931314428509

[bnjbvr]

Thanks!