Jsonschema

<!-- Release notes generated using configuration in .github/release.yml at v4.21.1 -->



**Full Changelog**: https://github.com/python-jsonschema/jsonschema/compare/v4.21.0...v4.21.1

<!-- Release notes generated using configuration in .github/release.yml at v4.21.0 -->

What's Changed
* Fix the behavior of `enum` in the presence of `0` or `1` to properly consider `True` and `False` unequal (1208).
* Special case the error message for `{min,max}{Items,Length,Properties}` when they're checking for emptiness rather than true length.

New Contributors
* otto-ifak made their first contribution in https://github.com/python-jsonschema/jsonschema/pull/1208

**Full Changelog**: https://github.com/python-jsonschema/jsonschema/compare/v4.20.0...v4.21.0

* Properly consider items (and properties) to be evaluated by `unevaluatedItems` (resp. `unevaluatedProperties`) when behind a `$dynamicRef` as specified by the 2020 and 2019 specifications.
* `jsonschema.exceptions.ErrorTree.__setitem__` is now deprecated. More broadly, in general users of `jsonschema` should never be mutating objects owned by the library.

**Full Changelog**: https://github.com/python-jsonschema/jsonschema/compare/v4.19.2...v4.20.0

<!-- Release notes generated using configuration in .github/release.yml at v4.19.2 -->

* Fix the error message for additional items when used with heterogeneous arrays.
* Don't leak the `additionalItems` keyword into JSON Schema draft 2020-12, where it was replaced by `items`.

**Full Changelog**: https://github.com/python-jsonschema/jsonschema/compare/v4.19.1...v4.19.2

<!-- Release notes generated using configuration in .github/release.yml at v4.19.1 -->

What's Changed
* Allow single label hostname in format string by swaeberle in https://github.com/python-jsonschema/jsonschema/pull/1164

New Contributors
* swaeberle made their first contribution in https://github.com/python-jsonschema/jsonschema/pull/1164

**Full Changelog**: https://github.com/python-jsonschema/jsonschema/compare/v4.19.0...v4.19.1

<!-- Release notes generated using configuration in .github/release.yml at v4.19.0 -->

* Importing the `Validator` protocol directly from the package root is deprecated. Import it from `jsonschema.protocols.Validator` instead.
* Automatic retrieval of remote references (which is still deprecated) now properly succeeds even if the retrieved resource does not declare which version of JSON Schema it uses. Such resources are assumed to be 2020-12 schemas. This more closely matches the pre-`referencing` library behavior.

**Full Changelog**: https://github.com/python-jsonschema/jsonschema/compare/v4.18.6...v4.19.0