pytest deprecation warnings

[pkienzle]

Looking at the output of test (ubuntu-latest, 3.11) I see the following deprecations, which will likely turn into errors in future versions.

 =============================== warnings summary ===============================
../../../../../opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/pytools/persistent_dict.py:63
  /opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/pytools/persistent_dict.py:63: RecommendedHashNotFoundWarning: Unable to import recommended hash 'siphash24.siphash13', falling back to 'hashlib.sha256'. Run 'python3 -m pip install siphash24' to install the recommended hash.
    warn("Unable to import recommended hash 'siphash24.siphash13', "

sasmodels/resolution.py: 136 warnings
  /home/runner/work/sasmodels/sasmodels/sasmodels/resolution.py:595: DeprecationWarning: `scipy.integrate.romberg` is deprecated as of SciPy 1.12.0and will be removed in SciPy 1.15.0. Please use`scipy.integrate.quad` instead.
    total = romberg(_int_w, 0, w, args=(qi,),

sasmodels/resolution.py: 136 warnings
  /home/runner/work/sasmodels/sasmodels/sasmodels/resolution.py:597: DeprecationWarning: Conversion of an array with ndim > 0 to a scalar is deprecated, and will error in future. Ensure you extract a single element from your array before performing this operation. (Deprecated NumPy 1.25.)
    result[i] = total/w

sasmodels/sasview_model.py::test_cylinder
  /opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/_pytest/python.py:163: PytestReturnNotNoneWarning: Expected None, but sasmodels/sasview_model.py::test_cylinder returned array([0.4255684]), which will be an error in a future version of pytest.  Did you mean to use `assert` instead of `return`?
    warnings.warn(

sasmodels/sasview_model.py::test_rpa
  /opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/_pytest/python.py:163: PytestReturnNotNoneWarning: Expected None, but sasmodels/sasview_model.py::test_rpa returned array([0.001]), which will be an error in a future version of pytest.  Did you mean to use `assert` instead of `return`?
    warnings.warn(

[krzywon]

../../../../../opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/pytools/persistent_dict.py:63
/opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/pytools/persistent_dict.py:63: RecommendedHashNotFoundWarning: Unable to import recommended hash 'siphash24.siphash13', falling back to 'hashlib.sha256'. Run 'python3 -m pip install siphash24' to install the recommended hash.
warn("Unable to import recommended hash 'siphash24.siphash13', "

This warning is now fixed in #613.