Nexus delaunay vertices failures due to scipy deprecations

[prckent]

Describe the bug
https://cdash.qmcpack.org/CDash/testDetails.php?test=27069120&build=426755

ntest_nexus_numerics is failing with the errors below on multiple machines. The machines have py-scipy@1.11.1

I see via https://docs.scipy.org/doc/scipy/release/1.11.0-notes.html#expired-deprecations that The vertices keyword of scipy.spatial.Delauney.qhull has been removed (use simplices).

Test output

Test name     : numerics
Test sublabel : test_convex_hull
Test exception: "AttributeError: 'Delaunay' object has no attribute 'vertices'"
Test backtrace:
  File "/scratch/pk7/QMCPACK_CI_BUILDS/qmcpack/nexus/bin/nxs-test", line 478, in run
    self.operation()
  File "/scratch/pk7/QMCPACK_CI_BUILDS/qmcpack/nexus/bin/nxs-test", line 726, in numerics
    nunit_all()
  File "/scratch/pk7/QMCPACK_CI_BUILDS/qmcpack/nexus/bin/nxs-test", line 362, in nunit_all
    run_external_unit_test(test_name,unit_test)
  File "/scratch/pk7/QMCPACK_CI_BUILDS/qmcpack/nexus/bin/nxs-test", line 388, in run_external_unit_test
    unit_test()
  File "/scratch/pk7/QMCPACK_CI_BUILDS/qmcpack/nexus/tests/unit/test_numerics.py", line 294, in test_convex_hull
    hull = convex_hull(points)
  File "/scratch/pk7/QMCPACK_CI_BUILDS/qmcpack/nexus/lib/numerics.py", line 1389, in convex_hull
    v = tri.vertices[ni]

Test status: fail

To Reproduce

Run develop nexus tests with scipy >=1.11

Expected behavior

Tests pass