Python-rtmidi

Fixes:

- Changed CI build configuration, so that auditwheel no longer puts a copy of
libasound in the Linux binary wheels - overriding the system libasound -
which prevented the `_rtmidi` extension module shared library from being
loaded on systems, where the ALSA plugin library path is not
`/usr/lib64/alsa-lib`, specifically on Debian-based distros. (190)
- Replace `pip` with `python -m pip` everywhere in in the installation
documentation and fixed some minor typos .

Changes:

- Removed obsolete Python 2 compatibility code in the `_rtmidi` module and
references to Python 2 unicode type in its docstrings.

Project infrastructure:

- Enabled CI builds for Python 3.12 (182).
- Updated cibuildwheel version used by CI to 2.16.
- Added Python 3.12 to meta-data classifiers in `pyproject.toml`.
- Added Python 3.12 to `tox.ini`, removed Python 3.7.
- Only use custom meson install script to byte-compile installed Python
modules if meson version <= 1.2.0.
- Updated latest Python version mentioned in windows install docs.
- Updated `requirements-dev.txt` with `pip-compile` (183).

Fixes:

- Fixed linting errors in `send_all.py` example (184).
- Fixed (no)gil/except declarations on MIDI in callback and
`MidiOut.sendMessage` (185).

The GIL is acquired in any case for MIDI in callback and C++ `sendMessage`
call, since Cython needs to check for exceptions.

Suppress related Cython compilation performance hints.

Also remove wrong statement about the GIL being released in docstring for
`send_message`.
- Fixed errors and check for empty message correctly when passing an iter- or
generator instead of a sequence to `MidiOut.send_message` (186, 188).

Fixes:

- Fixed building with `meson-python` >= 0.14.0 (177).

Fixes:

- Fixed Cython compilation errors and warnings (174).

Project infrastructure:

- Updated `requirements-dev.txt` with `pip-compile` (173).
- Updated minimum Python version declared in `pyproject.toml` to 3.8.

Documentation:

- Updated minimum Python version (3.8) stated in readme and docstring.

Changes:

- Added `send_all.py` script to examples (167).

Project infrastructure:

- Fixed macOS arm64 binary wheels built by CI without CoreMIDI support (169).

Changes:

- Updated `rtmidi` submodule (156).

Documentation:

- Updated installation documentation (165).
- Updated contributing guide (165).
- Removed Python 3.7 from meta-data classifiers in `pyproject.toml`(dfb3800).

Project infrastructure:

- Changed the build back-end to meson-python (161).
- Fixed broken macOS arm64 binary wheels built by CI (161).
- Fixed missing JACK backend API support in Linux aarch64 binary wheels built
by CI (161).
- Improved tests for binary wheels built by CI (162).
- Cleaned up GitHub actions workflow definitions (163).
- Fixed test coverage report target in Makefile (164).