Add pyproject.toml for packaging aboutcode.pipeline module #1351

[tdruez]

The dist archives can be manually built with:

$ cd scancode.io
$ source .venv/bin/activate
$ pip install flot
$ flot --pyproject pipeline-pyproject.toml --sdist --wheel --output-dir dist/

Also, regarding #1358 (comment), it seems that using the aboutcode.pipeline works fine:

pip install aboutcode.pipeline --find-links=scancode.io/dist --no-index --no-cache-dir
# Successfully installed aboutcode.pipeline-0.1

pip install aboutcode_pipeline --find-links=scancode.io/dist --no-index --no-cache-dir
# Successfully installed aboutcode_pipeline-0.1

pip install aboutcode-pipeline --find-links=scancode.io/dist --no-index --no-cache-dir
# Successfully installed aboutcode-pipeline-0.1

@keshav-space could you adapt and add the pypi-release-abc-pipeline.yml (let's use pypi-release-aboutcode-pipeline.yml) from https://github.com/nexB/scancode.io/pull/1332/files#diff-bbcc61089df1f0d385697aff0c2da0e9c972d8cf73acfe27f8cb437df2e92b46

Let's make sure we have a separate tag convention to trigger the releases of aboutcode.pipeline independently of the ScanCode.io releases.

This is fixes #1351

[keshav-space]

@tdruez, I've added the workflow to publish aboutcode.pipeline on PyPI, i've commented out the automatic trigger since we want to do the release manually.

[tdruez]

@keshav-space I've enabled the automatic build/publish on tag. I've removed the release addition in GH though, not sure we want to put those releases there.