Built-in support for numpy data-types

[lunik1]

Description

Hi,

Would there be any interest in adding support for numpy datatypes? Currently, attempting to encode these fails:

import msgspec.json as mjson
import numpy as np

mjson.encode(np.float64(1.0))

Traceback (most recent call last):
  File "<input>", line 4, in <module>
    mjson.encode(np.float64(1.0))
TypeError: Encoding objects of type numpy.float64 is unsupported

This seems like quite a common use case given the popularity of numpy, and to me it seems there are fairly obvious target data JSON types in most situations.

OTOH I appreciate that this can be done via extensions and that trying to support every third party library under the sun is like painting the Forth Bridge.