Update deprecated scipy.integrate.trapz to trapezoid

[scottyhq]

DeprecationWarning: 'scipy.integrate.trapz' is deprecated in favour of 'scipy.integrate.trapezoid' and will be removed in SciPy 1.14.0

Used here:

• https://tutorial.xarray.dev/advanced/apply_ufunc/dask_apply_ufunc.html?highlight=trapz#basics
• https://tutorial.xarray.dev/advanced/apply_ufunc/core-dimensions.html?highlight=trapz#