Log Message:
py-numexpr: updated to 2.7.3

Changes from 2.7.2 to 2.7.3
---------------------------
- Pinned Numpy versions to minimum supported version in an effort to alleviate
  issues seen in Windows machines not having the same MSVC runtime installed as
  was used to build the wheels.
- ARMv8 wheels are now available, thanks to `odidev` for the pull request.

Changes from 2.7.1 to 2.7.2
---------------------------
- Support for Python 2.7 and 3.5 is deprecated and will be discontinued when
  `cibuildwheels` and/or GitHub Actions no longer support these versions.
- Wheels are now provided for Python 3.7, 3.5, 3.6, 3.7, 3.8, and 3.9 via
  GitHub Actions.
- The block size is now exported into the namespace as `numexpr.__BLOCK_SIZE1__`
  as a read-only value.
- If using MKL, the number of threads for VML is no longer forced to 1 on loading
  the module. Testing has shown that VML never runs in multi-threaded mode for
  the default BLOCKSIZE1 of 1024 elements, and forcing to 1 can have deleterious
  effects on NumPy functions when built with MKL.
- Use of `ndarray.tostring()` in tests has been switch to `ndarray.tobytes()`
  for future-proofing deprecation of `.tostring()`, if the version of NumPy is
  greater than 1.9.
- Added a utility method `get_num_threads` that returns the (maximum) number of
  threads currently in use by the virtual machine. The functionality of
  `set_num_threads` whereby it returns the previous value has been deprecated
  and will be removed in 2.8.X.