Python as checkdepends (or optdepends)

I think that python may not actually be a mandatory dependency for this package. Here are a few reasons why:

• its README.md doesn't mention python as a dependency;
• looking for dependencies from other distros shows no trace of python (e.g., Debian, Alpine);
• building in a clean chroot without python succeeds;
• running meson test -C build succeeds;

However, I'd say that we should add the check() function. I have already developed one (see below) and it seems that the package comes with two suits of tests, one of which requires pip and pytest.

checkdepends=('python-pip' 'python-pytest')

check() {
  export LD_LIBRARY_PATH="$srcdir/build/libvips"
  meson test -C build
  pip install pyvips[test] --break-system-packages
  pytest -k "not test_text" -sv --log-cli-level=WARNING vips-$pkgver/test/test-suite
}

I was thinking of contributing two separate patches, one for removing the python dependency and a second one to add check() and checkdepends. I would contribute the second one after the first one to avoid merge conflicts. Let me know what you think!