Covbadge

[stefsmeets]

Description

This PR adds a workflow based on coverage.py and gists to generate a coverage badge. The advantage of this is that no third party service is needed.

Closes #369

Instructions to review the pull request

Create a python-template-test repo on GitHub (will be overwritten if existing)

cd $(mktemp -d --tmpdir py-tmpl-XXXXXX)
cookiecutter -c <pr-branch> https://github.com/<pr-user>/python-template
# Fill with python-template-test info
cd python-template-test
git init
git add --all
git commit -m "First commit"
git remote add origin https://github.com/<you>/python-template-test
git push -u origin main -f
python -m venv env
source env/bin/activate
python -m pip install --upgrade pip setuptools
python -m pip install '.[dev,publishing]'

[egpbos]

Thanks for taking the time for this!

Before putting more effort in, though, let's finish the discussion in #369 that @bouweandela started.