Openfisca-core

> Note: Version `38.0.1` has been unpublished as was deployed by mistake.
> Please use versions `38.0.2` and subsequents.

> Note: Version `38.0.0` has been unpublished as `35.11.1` introduced a bug
> preventing users to load a tax-benefit system. Please use versions `38.0.2`
> and subsequents.

New Features

- Upgrade OpenAPI specification of the API to v3 from Swagger v2.
- Continuously validate OpenAPI specification.

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)).

> Note: Version `37.0.2` has been unpublished as `35.11.1` introduced a bug
> preventing users to load a tax-benefit system. Please use versions `38.0.2`
> and subsequents.

Technical changes

- Always import numpy

> Note: Version `37.0.1` has been unpublished as `35.11.1` introduced a bug
> preventing users to load a tax-benefit system. Please use versions `38.0.2`
> and subsequents.

Technical changes

- Unify casing of NumPy.

> Note: Version `37.0.0` has been unpublished as `35.11.1` introduced a bug
> preventing users to load a tax-benefit system. Please use versions `38.0.2`
> and subsequents.

Deprecations

- In _periods.Instant_:
- Remove `period`, method used to build a `Period` from an `Instant`.
- This method created an upward circular dependency between `Instant` and `Period` causing lots of trouble.
- The functionality is still provided by `periods.period` and the `Period` constructor.

Migration details

- Replace `some_period.start.period` and similar methods with `Period((unit, some_period.start, 1))`.

> Note: Version `36.0.0` has been unpublished as `35.11.1` introduced a bug
> preventing users to load a tax-benefit system. Please use versions `38.0.2`
> and subsequents.

Breaking changes

- In `ParameterScaleBracket`:
- Remove the `base` attribute
- The attribute's usage was unclear and it was only being used by some French social security variables