To upgrade to Ember v6, we need to resolve the ember template-action deprecation present in the file below:

addon/components/cp-panel/template.hbs
toggle=(component 'cp-panel-toggle' on-click=(action 'toggleIsOpen') isOpen=this.isOpen)
with:
toggle=(component 'cp-panel-toggle' on-click=this.toggleIsOpen isOpen=this.isOpen)

As part of this resolution, we will have to convert the file addon/components/cp-panel/component.js to the Ember class-based component.