Fix build on maturin 0.15.2 and above

[evilmav]

Describe the bug

Maturin build fails starting with 0.15.x with

Warning: Couldn't find the symbol `PyInit_pyqir` in the native library. Python will fail to import this module. If you're using pyo3, check that `#[pymodule]` uses `pyqir` as module name

and failure to import the pyqir._native module at runtime. The behavior might be related to the change in 0.15.2: https://github.com/PyO3/maturin/pull/1608

To Reproduce

Steps to reproduce the behavior:

1. Install a recent maturin version
2. cd into pyqir/
3. Run maturin build --release -F llvm14-0
4. See warning

Expected behavior

The warning should not happen. The resulting module should be importable.

System information

• Tried on arch with maturin 1.0.1 installed as well as during NixOS packaging, where the package build with 23.05 stable realese shipping maturin 14.17 but not the unstable branch.