Improve build and release

[lfoppiano]

This PR improves the automation:

• adds Github actions for build and release
• replace the old setup.py with the new pyproject.toml which integrates with bump-my-version for the release (also it has the advantage to integrate with the requirements.txt so that dependencies are managed in a single place)
• the release can be done simply by running bump-my-version bump patch, then push the tags, and github action will do the rest.

NOTE: the secret of the project must be added to be able to push on pypi.

[lfoppiano]

I've tested on my fork and the release can be done automatically. Once this is merged, is necessary to add the action secret PYPI_API_TOKEN to be able to push on pypy.

I've made a sample test project on pypi: https://pypi.org/project/grobid-client-python-test/ (I will remove it once this is merged)

[lfoppiano]

For the release, is necessary to install bump-my-version

bump-my-version show-bump
0.0.11 ── bump ─┬─ major ─ 1.0.0
                ├─ minor ─ 0.1.0
                ╰─ patch ─ 0.0.12

for releasing

bump-my-version bump [major|minorpatch]

And then

git push
git push --tags

et voilá

[kermitt2]

Hi Luca,

For leaving setup.py, the readme must be updated.