Leonardo-api

Fixed
- Fixed image upload methods (headers should be purged before poking s3)
- Fixed session headers update to much more generic

Fixed
- Fixed headers update methods (possible async bug fix)

Changed
- Fixed wait_for_image_generation method (default is 0 now)
- Updated GitHub workflows (Python 3.12 added for linters)
- Bumped requirements

Changed
- Updated metadata
- Updated GitHub workflows

Changed
- Updated metadata

Changed
- Fixed linters warnings
- README.md