Build Python wheels for musl Linux

[redeboer]

Closes #658

• As a follow-up to Build wheels for Python package #549, wheels for PyPI are now also built on musl Linux.
• Introduces an intermediate step to merge the wheels into one artifact. This is more convenient for testing, see comment

[redeboer]

Tested with Docker:

rm -r wheels/
gh run download -n wheels -D wheels --repo tamasfe/taplo 10529188669
docker build -t test-pypi-taplo-musl .
docker run -it --rm test-pypi-taplo-musl
# taplo help

Dockerfile:

FROM python:3.8-alpine3.18
WORKDIR /app
COPY wheels/ wheels/
RUN pip install --no-index --find-links wheels/ taplo
CMD ["/bin/sh"]

Running the above with artifacts from 10529180972 (without musl wheels) instead of 10529188669 fails.

[redeboer]

@panekj could you review?