Antares-study-version

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- Add missing operators inside TripletVersion class
- Explicitly export StudyVersion and SolverVersion to avoid mypy issues
- Implement upgrade for StudyVersion 9.0

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- Minor code improvements
- Allow upgrade with empty fields inside `study.antares` file.
- Add `py.typed` file to avoid mypy issue in projects importing the code

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Features

This version allows to manage the versions of Antares raw studies (studies on disk).

It contains a command line application to create a new raw study in the version of your choice,
and to update an existing raw study to a newer version.

The new CLI also allows to display the details of a raw study and to list the available versions.
Run the following command to get more information:

bash
antares-study-version --help

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Fixes

* **model:** avoid deprecation warning about usage of `NotImplemented` in boolean context

Tests

* replace [pytest-freezegun](https://pypi.org/project/pytest-freezegun/) lib
by [pytest-freezer](https://pypi.org/project/pytest-freezer/)

Docs

* `README.md`: update doc, fix typo, add a link to the change log

Build

* create [CHANGELOG.md](CHANGELOG.md) and update the release date
* add `scripts/update_version.py` script to create or update the changelog

CI

* add missing dependency [pytest-freezer](https://pypi.org/project/pytest-freezer/) required for type checking
* create the `.github/workflows/python-package.yml` GitHub workflow for code style and typing check

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Features

* First release of the project.