An error of example/pinn_forward/Helmholtz_Dirichlet_2d_HPO.py

[lijialin03]

Function 'gp_minimize' of package 'skopt (scikit-optimize)' is used in this example and an error has been reported like,

The reason is that 'np.int' used in skopt was deprecated in NumPy 1.20. The newest NumPy is version 1.25.
My skopt version is 0.9.0. I think it is the latest version in https://pypi.org/search/?q=scikit-optimize. So this example may require NumPy 1.20 or lower while there is no version requirements of NumPy in requirements.txt.