ComplexWarning fix

Fix: ComplexWarning Moved (#10)

* Fix: `ComplexWarning` Moved

Since NumPy 1.25+ and breaking in 2.0+, `ComplexWarning`
moved into its own sub-namespace for `exceptions`.

Ref.:
- https://numpy.org/doc/1.25/reference/generated/numpy.exceptions.ComplexWarning.html
- https://numpy.org/doc/stable/reference/generated/numpy.exceptions.ComplexWarning.html

* Support NumPy 2.0+

v.1.1.6

Full Changelog: v.1.1.8...v.1.1.6

v1.1.5

What's Changed

• Changed TOL variable to 1 by @PZiso in #2
• exposed tol variable as naff() input, non-zero mean as warning by @b-riemann in #3
• Changed deprecated numpy functions to builtin ones by @PZiso in #5

Full Changelog: https://github.com/nkarast/PyNAFF/commits/1.1.5