Cleaner artifact generation

[etpinard]

inspired by https://github.com/sglyon/PlotlyBase.jl/blob/master/deps/generate_artifacts.jl so that we now use the following official methods exported from Pkg.Artifacts:

• create_artifacts
• archive_artifact (which creates a new tarball and should work across platforms, unlike tar)
• bind_artifact! (which writes the Artifact.toml content)

Moreover, I think we'll be able to remove

https://github.com/etpinard/dash-textarea-autocomplete/blob/87314378dace4f76239832099a07a2558809a6fe/.github/workflows/tests.yml#L43-L52

that is, Pkg.add(url=\"$GITHUB_SERVER_URL/$GITHUB_REPOSITORY\", rev=\"$GITHUB_SHA\"); should just work now.

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Oh well, we don't need to merge this PR and maybe we shouldn't for now.

@Felix-Gauthier I think we have spent enough time on dash-textarea-autocomplete in the last 10 days or so. Consider this PR documentation for future dash-textarea-autocomplete work.

[Felix-Gauthier]

This looks great, we're better of using this one julia script than postbuild.sh + tweaks to CI

We could do a patch release after the holidays to use it 🚀