Add configurable python target to check-python

[fcollonval]

Fixes #237 by allowing to define a Python target to be checked through python -c "import <target>" instead of using the package name.

This can be done through a new cli option --check-imports or the env variable RH_CHECK_IMPORTS.

[fcollonval]

This has been hit in https://github.com/mamba-org/quetz/runs/4759614490

[codecov-commenter]

Codecov Report

Merging #238 (8cfbd40) into main (642d724) will decrease coverage by 0.03%.
The diff coverage is 85.36%.

@@            Coverage Diff             @@
##             main     #238      +/-   ##
==========================================
- Coverage   85.13%   85.09%   -0.04%     
==========================================
  Files          19       19              
  Lines        2307     2335      +28     
  Branches      298      302       +4     
==========================================
+ Hits         1964     1987      +23     
- Misses        246      251       +5     
  Partials       97       97              

Impacted Files	Coverage Δ
jupyter_releaser/python.py	79.48% <60.00%> (-4.10%)	⬇️
jupyter_releaser/cli.py	91.36% <100.00%> (+0.06%)	⬆️
jupyter_releaser/tests/conftest.py	98.57% <100.00%> (+0.03%)	⬆️
jupyter_releaser/tests/test_cli.py	99.04% <100.00%> (+0.01%)	⬆️
jupyter_releaser/tests/util.py	99.24% <100.00%> (+0.02%)	⬆️

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[blink1073]

Perhaps instead we should offer an array of imports, similar to conda-forge recipes?

[fcollonval]

I change the PR to be able to pass a list of --check-imports.

[blink1073]

Nice, thanks!