Asphalt-serialization

- Fixed overly restrictive dependency constraint on Asphalt core

- **BACKWARD INCOMPATIBLE** Upgraded dependencies:

- ``ruamel.yaml`` ⟶ 0.15+
- ``cbor2`` ⟶ ~5.0
- ``msgpack`` ⟶ ~1.0
- **BACKWARD INCOMPATIBLE** Removed the ``dumper_options`` parameter to ``YAMLSerializer``, as
``ruamel.yaml`` does not seem to support this anymore
- Added support for Python 3.10
- Dropped support for Python 3.5 and 3.6

- Fixed msgpack deprecation warnings by replacing the ``encoding="utf-8"`` unpacker option with
``raw=False``

- Added compatibility with Asphalt 4.0

- Fixed ``None`` not being accepted in place of a serializer configuration dictionary

- **BACKWARD INCOMPATIBLE** Migrated to Asphalt 3.0
- **BACKWARD INCOMPATIBLE** Upgraded cbor2 dependency to v4
- **BACKWARD INCOMPATIBLE** Improved the ability to customize the serialization of custom types in
serializers implementing the ``CustomizableSerializer`` interface by specifying a value for the
``custom_type_codec`` option. This replaces the ``custom_type_key`` and ``wrap_state`` options.