Openfisca-country-template

* Technical improvement.
* Details:
- Update openfisca-core version >= 41.0

* Technical improvement.
* Impacted areas: template setup script
* Details:
- Allows country-template to pass `check-style` makefile command

* Technical improvement.
* Impacted areas: template replacement script
* Details:
- Avoid `sed: RE error: illegal byte sequence` error when template contains `.DS_Store` files after GUI navigation in macOS

* Technical improvement.
* Impacted periods: all.
* Impacted areas: all.
* Details:
- Upgrade every dependencies & use their latest versions to use Python 3.9 and 3.10 and drop support of Python versions < 3.9 .

New features

- Upgrade Web API specification to OpenAPI v3.

Breaking changes

- Drop support for OpenAPI specification v2 and prior.
- Users relying on OpenAPI v2 can use [Swagger Converter](https://converter.swagger.io/api/convert?url=OAS2_YAML_OR_JSON_URL) to migrate ([example](https://web.archive.org/web/20221103230822/https://converter.swagger.io/api/convert?url=https://api.demo.openfisca.org/latest/spec)).

Breaking change

* Technical improvement.
* Details:
- Expire deprecated class `Bracket`.
- Functionality is now provided by `ParameterScaleBracket`