Fix errors with numpy2

[t-imamichi]

docplex raises an error with numpy 2.
This PR fixes them.

This PR also fixes an escape error of a docstring.

try:
    from docplex.cp.model import CpoModel
except Exception as ex:
    print(ex)
try:
    from docplex.mp.model import Model
except Exception as ex:
    print(ex)

docplex 2.27.239

`np.float_` was removed in the NumPy 2.0 release. Use `np.float64` instead.
`np.float_` was removed in the NumPy 2.0 release. Use `np.float64` instead.

this PR

[t-imamichi]

This change fixes the following syntax warning.

SyntaxWarning: invalid escape sequence '\?'
  '''From `name`, create an attachment name that is correct for DOcplexcloud.

[t-imamichi]

#12 fixed the issue.