[BUG] Numpy decode issue...

[bgyooPtr]

Description

The bug occurs when you type np.float32 into np.ndarray and run the json.dumps function.
Even though it has clearly been changed to a list through the to_dict function, an error occurs in json.dumps for some reason.

Add.....

The cause of this bug is that the elements of the numpy array are specified as numpy type. (see code below)

I think it's a bug in dataclass_json.

Code snippet that reproduces the issue

from dataclasses import dataclass, field
from dataclasses_json import dataclass_json, config
import numpy as np

import json


@dataclass_json
@dataclass
class Foo:
    a: np.ndarray = field(default=np.array([0.0, 0.0, 0.0, 0.0, 0.0]), metadata=config(decoder=np.asarray))


@dataclass_json
@dataclass
class Bar:
    a: np.ndarray = field(
        default=np.array([0.0, 0.0, 0.0, 0.0, 0.0], dtype=np.float32), metadata=config(decoder=np.asarray)
    )


a = Foo()
print(a)
b = Bar()
print(b)

json.dumps(a.to_dict())
json.dumps(b.to_dict())  # ERROR TypeError: Object of type float32 is not JSON serializable

b_dict = b.to_dict()
print(isinstance(b_dict["a"], list))  # True
print(b_dict["a"].__class__.__name__)  # list
print(type(b_dict["a"][0]))  # numpy.float32

Describe the results you expected

Note the last line

Python version you are using

3.8

Environment description

black==22.12.0
certifi==2023.7.22
charset-normalizer==3.3.1
click==8.1.7
coverage==7.3.2
dataclasses-json==0.5.9
docstring-parser==0.15
exceptiongroup==1.1.3
falcon==2.0.0
flake8==5.0.4
ghp-import==2.1.0
gitdb==4.0.11
GitPython==3.1.40
hug==2.6.1
hypothesis==6.88.1
idna==3.4
importlib-metadata==6.8.0
iniconfig==2.0.0
Jinja2==3.1.2
livereload==2.6.3
Mako==1.2.4
Markdown==3.5
MarkupSafe==2.1.3
marshmallow==3.20.1
marshmallow-enum==1.5.1
mccabe==0.7.0
mergedeep==1.3.4
mkdocs==1.3.0
mkdocs-material==8.5.4
mkdocs-material-extensions==1.3
mypy==1.6.1
mypy-extensions==1.0.0
numpy==1.24.4
packaging==23.2
pathspec==0.11.2
pdocs==1.2.0
platformdirs==3.11.0
pluggy==1.3.0
portray==1.8.0
pycodestyle==2.9.1
pyflakes==2.5.0
Pygments==2.16.1
pymdown-extensions==10.3.1
pypng==0.0.21
PyQt5==5.15.10
PyQt5-Qt5==5.15.2
PyQt5-sip==12.13.0
pytest==7.4.3
pytest-cov==2.12.1
python-dateutil==2.8.2
PyYAML==6.0.1
pyyaml_env_tag==0.1
requests==2.31.0
scipy==1.10.1
simplejson==3.19.2
six==1.16.0
smmap==5.0.1
sortedcontainers==2.4.0
termcolor==2.3.0
toml==0.10.2
tomli==2.0.1
tornado==6.3.3
typing-inspect==0.9.0
typing_extensions==4.8.0
urllib3==2.0.7
watchdog==3.0.0
yaspin==2.4.0
zipp==3.17.0