* Python 3.7 has been dropped.
* Introduce `attrs.NothingType`, for annotating types
consistent with `attrs.NOTHING`.
* Allow mutating `__suppress_context__` and `__notes__` on
frozen exceptions.
* `attrs.converters.optional()` works again when taking
`attrs.converters.pipe()` or another Converter as its
argument.
* *attrs* instances now support `copy.replace()`.
* `attrs.validators.instance_of()`'s type hints now allow for
union types.
* For example: `instance_of(str | int)`
OBS-URL: https://build.opensuse.org/package/show/devel:languages:python/python-attrs?expand=0&rev=55
