Spec-classes

(Same as 1.2.3).

Identical to 1.2.2. Attempting to fix artifact issue on PyPI.

This is a patch release that fixes an issue where passing dictionaries for dictionary types is conflated with constructor arguments.

This is a minor patch release that adds a few minor feature extensions and fixes a few bugs. In particular:

- Added support for constructing nested spec-classes from a dictionary of arguments to pass to the nested spec-class constructor (e.g. `MyClass(nested={"attr": "value"})`.
- Added `*polymorphic` and `*constructor` cached attributes to `Attr`.
- Fixed dataclasses compatibility on non-bootstrapped spec-classes (lookups on `__dataclass_fields__` will now properly trigger bootstrapping and return the appropriate spec-class attributes).
- Fixed type-checks involving `Literal` annotations.

This is a minor feature release that:

- Adds explicit support for Python 3.10 (and fixes some minor inconsistencies on this version)
- Improves compatibility with `dataclasses` tooling (e.g. `replace`).
- Adds a new "compact" representation of spec-classes, and default to using it for nested spec-classes.
- Migrates the project tooling to use Poetry.

This is a minor release that improves the labelling of `typing` types (e.g. `typing.Any` used to be "_SpecialForm", and is now "Any").