switch to scipy.integrate.simpson

scipy.integrate.simps was deprecated in scipy 1.12.0 and will be removed in 1.14
https://docs.scipy.org/doc/scipy/release/1.12.0-notes.html#deprecated-features

This does introduce a requirement of scipy>=1.6.0, which is when scipy.integrate.simpson was introduced
https://docs.scipy.org/doc/scipy/release/1.6.0-notes.html#scipy-integrate-improvements

allantools/allantools.py

@@ -111,7 +111,7 @@
 import json
 import numpy as np
 from scipy import interpolate # used in psd2allan()
-from scipy.integrate import simps # used in psd2allan()
+from scipy.integrate import simpson # used in psd2allan()
 
 from . import ci # edf, confidence intervals
 
@@ -1756,7 +1756,7 @@ def psd2allan(S_y, f=1.0, kind='adev', base=2):
  for idx, mj in enumerate(m)])
  integrand = np.insert(integrand, 0, 0.0, axis=1)
  f = np.insert(f, 0, 0.0)
- ad = np.sqrt(2.0 * simps(integrand, f))
+ ad = np.sqrt(2.0 * simpson(integrand, f))
  return taus_used, ad