Add pyproject.toml for the ssg package

[vojtapolasek]

Description:

• add pyproject.toml to the repo
• use setuptools_scm plugin to infer dynamic version from our repo
  • since we are handling tags in an uncommon way, I needed to create a special command for this case. See the comment in the file for explanation.
• currently the package contains only contents of the ssg folder

Rationale:

• this enables easier consuming of the ssg library by external contributors. They could use something like

pip install git+https://github.com/ComplianceasCode/content@v0.1.75

How to test

1. create a new virtual environment with Python >= 3.8
2. run pip3 install git+https://github.com/vojtapolasek/content@add_ssg_poetry
3. run python
4. import ssg.build_yaml
5. alternatively clone the content repo and try building some product with this ssg package

[openshift-ci]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[github-actions]

Start a new ephemeral environment with changes proposed in this pull request:

Fedora Environment

Oracle Linux 8 Environment

[qlty-cloud-legacy]

Code Climate has analyzed commit d5f2628 and detected 0 issues on this pull request.

The test coverage on the diff in this pull request is 100.0% (50% is the threshold).

This pull request will bring the total coverage in the repository to 60.9% (0.0% change).

View more on Code Climate.

[marcusburghardt]

I have tested it in a virtualenv, installing from your fork and it worked fine. I could call and use some functions in very simple tests. I only had some comments to better understand the versions, but so far it is good.

[marcusburghardt]

LGTM. Nice to have this option now.