Jsonschema-spec

Bug fixes
* Accessor store resolved references fix 58

Bug fixes
* `FilePathReader` read relative path fix 39

Features
* Add `resolve` context method for `SchemaPath` 31

Changelog
* Bump referencing from 0.24.4 to 0.29.0 25

Changelog
* Python 3.7 support dropped 23
* Remove jsonschema dependency in favor of referencing and jsonschema-specifications 12
* `SchemaPath.from_path` factory method added

Deprecations
* `Spec` class name is deprecated. Use `SchemaPath` instead.
* `spec_url` parameter is deprecated. Use `base_uri` instead.
* `ref_resolver_handlers` parameter is deprecated. Use `handlers` instead.

Changelog
* lock typing-extensions just for python37 22