Release OpenCV 4.9.0

OpenCV 4.8.1 release with security fix.

OpenCV 4.8.0 release with typing fix.

Release OpenCV 4.8.0.

Merge pull request opencv#803 from asmorkalov/as/license

Renamed license to match Pypi classifier.

OpenCV 4.7.0 with various distribution bug fixes.

- Mac OS 11 support.
- Old Linux support with zlib version older than 1.9.
- Package build fixes for Python 11 on Musl C based system (Alpine).

OpenCV 4.7.0 release preparation

- Python 3.7 as baseline
- Python 3.11 support
- Various updates

Merge pull request opencv#668 from asenyaev/asen/check_latest_commits…

…_4.x

Update master branch for 4.6.0 release

Merge pull request opencv#671 from asenyaev/asen/3.4.18_release

Update 3.4 branch for 3.4.18 release

Merge pull request opencv#632 from asenyaev/asen/fix_current_builds

Defined ffmpeg version for MacOS and Windows Server version in Github Actions