Update the DataSource factory - should be a SOFT7Instance factory
instead with proper validation of property metadata and more.

Add pytest and pytest-cov dependencies, along with a new `testing`
installable extra.

Remove tests for the now re-written SOFT7EntityPropertyType (previously
an Enum, now just a Literal collection with an associated mapping).

Satisfy mypy

Also, rename create_entity() to create_datasource().

Ensure the create_datasource() function returns an instantiated model.

This can now be used in both the SOFT7DataSource model as well as the
new DataSourceDimensions model.

Add `requests-mock` dependency. Consider using "python" backend for
OTELib instead to avoid mocking requests.

Remove all filterwarnings from pytest config.

New test using python otelib backend.

Added test for serializing

All the serialization tests (including JSON Schema) must be extended to
ensure not just that it _can_ be serialized, but that the content is
also what would be expected.

Implemented as a pydantic model_serializer in "wrap" mode.

Temporarily changed the otelib dependency to point to a git branch on
GitHub that implements migration to pydantic v2.

Make the namespace an AnyUrl.

Quick (but proper) solutions to ever so slightly decrease the number of
uncovered lines.

Specifically, move all the "helper"/utility functionalities from
`datasource_factory.py` to a new `soft7_instance.py` under
pydantic_models.

Run hooks on all files, upgrading them accordingly.

Make factory functions importable from `s7.factories` as `create_*`,
where * matches the name of any `*_factory.py` file in the folder.

Split ruff hook for core code base code and non-core.

Started to flesh out an OTEAPI function strategy plugin for converting
between a parsed data source to a SOFT7 Entity instance.

Missing finalizing example in notebook.

There is a design issue here with nested entities that should be fixable
in a more elegant way

Need to fix setting ClassVar on EntityInstance and the validator for the
same.

Add a YAML parse strategy for OTEAPI.

See issue #395 in oteapi-core to follow up on when this ignore statement
can be removed.

Focus on:
- the entity_instance factory
- the OTEAPI plugins
- the pydantic models

These should be removed when supporting Python 3.10+.

Pydantic does not support new-style type notation in Python 3.9.

Update pre-commit hooks

Update GH Actions.
Update ruff rules.

Finalize update to Python 3.10