9.0.0

❤️ contributors: @mgorny, @CTPaHHuK-HEbA

• 🐞 Linux: add failure handling to XOpenDisplay() call (fixes #246)
• 🚀 Mac: tiny improvement in monitors finding
• 🐛 Windows: refactored how internal handles are stored (fixes #198)
• 🐛 Windows: removed side effects when leaving the context manager, resources are all freed (fixes #209)
• CI: run tests via xvfb-run on GitHub Actions (#248)
• tests: enhance test_get_pixels.py, and try to fix a random failure at the same time (related to #251)
• tests: use PyVirtualDisplay instead of xvfbwrapper (#249)
• tests: automatic rerun in case of failure (related to #251)