Openfisca-extension-template

* Technical Changes
* Details:
* Migrate from CircleCI to Github Actions

* Technical change
* Details:
- Add tar.gz to PyPi to be used by conda to build conda package.

* Technical change
* Details:
- Migrate from deprecated Dependabot.com to GitHub-native Dependabot service
- Allows to track the dependencies updates according to new `.github/dependabot.yml` configuration file

* Minor change.
* Details:
- Add support for `flake8-bugbear` < 22

* Minor change.
* Details:
- Add support for `flake8-print` < 5

* Technical improvement.
* Details:
- Forces the installation of the new build each time `make build` is run
- CircleCI tests against the packaged version of this library
- When a branch is pushed first time, CircleCI creates a build and caches dependencies
- Subsequent pushes do not reinstall the build as it is already in cache
- If the code has been modified in between, changes will be ignored, and tests will fail