replace scipy.integrate.simps with simpson

[orbeckst]

• fix #281
• call scipy.integrate.simpson() instead of simps (available since scipy 1.6.0)
• remove even="last" kwarg (not used anymore in simpson())
• minimum required scipy >= 1.11.0 (Cartwright rule is used for even number of points)

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 81.63%. Comparing base (120c5dd) to head (23dfd1d). Report is 1 commits behind head on develop.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #282 +/- ## =========================================== - Coverage 81.68% 81.63% -0.06% =========================================== Files 15 15 Lines 2026 2015 -11 Branches 310 310 =========================================== - Hits 1655 1645 -10 Misses 276 276 + Partials 95 94 -1 ```

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[orbeckst]

What could be fixed, is fixed.