Remove composer version restriction

[bobvandevijver]

This has been added (bdd4652) as currently api-platform causes all pipelines to fail. When #3610 has been resolved, the limitation can be dropped again.

Also holds for:

• https://github.com/bolt/article
• https://github.com/bolt/configuration-notices-widget
• https://github.com/bolt/redactor
• https://github.com/bolt/weatherwidget