Fix multi python package publishing

[davidbrochart]

We now build Python packages in separate distribution directories, and upload them to PyPI independently. This also means publishing assets to PyPI and to NPM separately.

Fixes #200

[codecov-commenter]

Codecov Report

Merging #201 (300724f) into master (25f51b4) will decrease coverage by 0.03%.
The diff coverage is 87.50%.

@@            Coverage Diff             @@
##           master     #201      +/-   ##
==========================================
- Coverage   84.85%   84.81%   -0.04%     
==========================================
  Files          19       19              
  Lines        2271     2272       +1     
  Branches      280      281       +1     
==========================================
  Hits         1927     1927              
  Misses        248      248              
- Partials       96       97       +1     

Impacted Files	Coverage Δ
jupyter_releaser/lib.py	83.96% <83.33%> (-0.23%)	⬇️
jupyter_releaser/cli.py	91.30% <100.00%> (ø)

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[davidbrochart]

The problem is that no matter if we build packages in separate directories, we install them in a common directory before uploading them to PyPI, so it's useless.
What I did is to provide a list of packages in the form "package_path:package_name", like so:
https://github.com/jupyter-server/jupyverse/blob/d02cde63d0bf2e47fb5d9310b74a9fc6c95b9ce1/pyproject.toml#L22
I added the package_name because we need the package name to map the distribution files to their PyPI token.

I checked that it works fine with jupyverse.

[davidbrochart]

The distribution file name is something like my_package-0.1.2.tar.gz or my_package-0.1.2-py3-none-any.whl, and we could imagine a package name being my_package and another one being my_package_2, and both would match this condition, so this is not great. Maybe we could include the version spec in the condition, but at first sight tests were failing when doing so.

[jtpio]

Thanks @davidbrochart for looking into this.

[jtpio]

We'll need to revert that one (and similar below) to point to the releaser actions.

[davidbrochart]

This is ready to be merged, and jupyverse depends on it. Given that the multi-python packages feature is only used by jupyverse AFAIK, I think the current limitation is acceptable, and we can improve it in the future. The limitation is that the package names, given in the form:

python_packages = [".:jupyverse", "plugins/auth:fps-auth", "plugins/contents:fps-contents"]

must not start with the same name, e.g. something like that wouldn't work:

python_packages = [".:jupyverse", "plugins/auth:fps-auth", "plugins/contents:fps-auth2"]

[blink1073]

Thanks!