Bump pyo3 and rust numpy version to 0.19.0

[mtreinish]

Pyo3 0.19.0 and rust-numpy 0.19.0 were just released. This commit updates the version used in rustworkx to these latest releases. At the same time this updates usage of text signature for classes that was deprecated in 0.19.0 release. While not fatal for normal builds this would have failed clippy in CI because we treat warnings as errors.

[coveralls]

Pull Request Test Coverage Report for Build 5144317507

• 3 of 3 (100.0%) changed or added relevant lines in 3 files are covered.
• 15 unchanged lines in 4 files lost coverage.
• Overall coverage decreased (-0.05%) to 96.463%

---

Files with Coverage Reduction	New Missed Lines	%
src/shortest_path/all_pairs_dijkstra.rs	1	98.54%
src/traversal/mod.rs	2	96.23%
src/shortest_path/mod.rs	5	98.4%
src/iterators.rs	7	86.14%

Totals
Change from base Build 5143940500:	-0.05%
Covered Lines:	15082
Relevant Lines:	15635

---

💛 - Coveralls

[IvanIsCoding]

Oh wow my stubs test is failing. Probably if you put Optional in iterators.pyi for the array method it will fix it

[IvanIsCoding]

I ran it locally and I can confirm that changing https://github.com/Qiskit/rustworkx/blob/main/rustworkx/iterators.pyi#L71 to def __array__(self, _dt: Optional[np.dtype] = ...) -> np.ndarray: ... and adding the respective import solves the test problem

[mtreinish]

It must be caused by an upstream change in rust-numpy (or something around that). I'll edit the stub file, as I think it'd be good to try and get this in for 0.13.0 which besides #823 I think is ready.