Update RobotFramework to 5.x

[php-coder]

Changelogs:

• https://github.com/robotframework/robotframework/releases/tag/v5.0a1
• https://github.com/robotframework/robotframework/releases/tag/v5.0b1
• https://github.com/robotframework/robotframework/releases/tag/v5.0rc2
• https://github.com/robotframework/robotframework/releases/tag/v5.0
• https://github.com/robotframework/robotframework/releases/tag/v5.0.1rc1
• https://github.com/robotframework/robotframework/releases/tag/v5.0.1
• https://github.com/robotframework/robotframework/releases/tag/v5.1a1
• https://github.com/robotframework/robotframework/releases/tag/v5.1a2
• https://github.com/robotframework/robotframework/releases/tag/v5.1b1
• https://github.com/robotframework/robotframework/releases/tag/v5.1b2

Blocked by: #1535