Remove broken link

[christophfroehlich]

@mergifyio backport iron humble

[mergify[bot]]

backport iron humble

✅ Backports have been created

* [#259 Remove broken link (backport #257)](https://github.com/ros-controls/control.ros.org/pull/259) has been created for branch `iron` * [#260 Remove broken link (backport #257)](https://github.com/ros-controls/control.ros.org/pull/260) has been created for branch `humble`