v1.6.1

Fixed

• pip install microstructpy installs versions of numpy and MeshPy that
  the package works with: numpy below 2 and MeshPy below 2026. With numpy 2,
  the text files of the meshes cannot be read back, since numpy writes
  integers as np.int64(4), and tangent_sphere fails. With MeshPy
  2026, TetGen no longer keeps the elements of 3D meshes under
  max_volume. numpy below 2 has no wheels for Python 3.13 and later, so
  pip builds it from source there, which needs a compiler.

Changed

• The continuous integration also runs the tests on an installation without
  the pins of requirements.txt, as pip install microstructpy does, so
  that it sees the dependency versions that users get.