Yaml serializer fails with Numpy 2.0 #15792

from astropy.table import Table
import numpy as np
t = Table(dict(b=[0,1]), meta=dict(a=np.float64(1)))
t.write("bu.ecsv")
Table.read("bu.ecsv")

In [1]: from astropy.table import Table

In [2]: import numpy as np

In [3]: t = Table(dict(b=[0,1]), meta=dict(a=np.float64(1)))

In [4]: t.write("bu.ecsv")

In [5]: Table.read("bu.ecsv")
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
File ~/opt/anaconda3/envs/py311dev/lib/python3.11/site-packages/astropy/table/meta.py:431, in get_header_from_yaml(lines)
    430 try:
--> 431     header = yaml.load(header_yaml, Loader=TableLoader)
    432 except Exception as err:

File ~/opt/anaconda3/envs/py311dev/lib/python3.11/site-packages/yaml/__init__.py:81, in load(stream, Loader)
     80 try:
---> 81     return loader.get_single_data()
     82 finally:

File ~/opt/anaconda3/envs/py311dev/lib/python3.11/site-packages/yaml/constructor.py:51, in BaseConstructor.get_single_data(self)
     50 if node is not None:
---> 51     return self.construct_document(node)
     52 return None

File ~/opt/anaconda3/envs/py311dev/lib/python3.11/site-packages/yaml/constructor.py:60, in BaseConstructor.construct_document(self, node)
     59 for generator in state_generators:
---> 60     for dummy in generator:
     61         pass

File ~/opt/anaconda3/envs/py311dev/lib/python3.11/site-packages/yaml/constructor.py:413, in SafeConstructor.construct_yaml_map(self, node)
    412 yield data
--> 413 value = self.construct_mapping(node)
    414 data.update(value)

File ~/opt/anaconda3/envs/py311dev/lib/python3.11/site-packages/yaml/constructor.py:218, in SafeConstructor.construct_mapping(self, node, deep)
    217     self.flatten_mapping(node)
--> 218 return super().construct_mapping(node, deep=deep)

File ~/opt/anaconda3/envs/py311dev/lib/python3.11/site-packages/yaml/constructor.py:143, in BaseConstructor.construct_mapping(self, node, deep)
    141     raise ConstructorError("while constructing a mapping", node.start_mark,
    142             "found unhashable key", key_node.start_mark)
--> 143 value = self.construct_object(value_node, deep=deep)
    144 mapping[key] = value

File ~/opt/anaconda3/envs/py311dev/lib/python3.11/site-packages/yaml/constructor.py:100, in BaseConstructor.construct_object(self, node, deep)
     99 if tag_suffix is None:
--> 100     data = constructor(self, node)
    101 else:

File ~/opt/anaconda3/envs/py311dev/lib/python3.11/site-packages/yaml/constructor.py:292, in SafeConstructor.construct_yaml_float(self, node)
    291 else:
--> 292     return sign*float(value)

ValueError: could not convert string to float: 'np.float64(1.0)'

The above exception was the direct cause of the following exception:

YamlParseError                            Traceback (most recent call last)

(...)

InconsistentTableError: unable to parse yaml in meta header