Update RobotFramework to 6.x #1597
Description
Changelogs:
- https://github.com/robotframework/robotframework/releases/tag/v6.0rc1
- https://github.com/robotframework/robotframework/releases/tag/v6.0rc2
- https://github.com/robotframework/robotframework/releases/tag/v6.0
- https://github.com/robotframework/robotframework/releases/tag/v6.0.1
- https://github.com/robotframework/robotframework/releases/tag/v6.0.2
- https://github.com/robotframework/robotframework/releases/tag/v6.1a1
- https://github.com/robotframework/robotframework/releases/tag/v6.1b1
- https://github.com/robotframework/robotframework/releases/tag/v6.1rc1
- https://github.com/robotframework/robotframework/releases/tag/v6.1
- https://github.com/robotframework/robotframework/releases/tag/v6.1.1
Blocked by: #1571