Additional information

• version 8.2.0 (couldn't select it from dropdown as it wasn't available at the time of writing)
• start new project following '5 min quick start' guide
• add 'Angular Bootstrap Collapse' following docs (overview, api)
• add aria-expanded attribute according to section 'Accessibility'

Expected behavior
aria-expanded attribute is updated when interacting with the element.

Actual behavior
aria-expanded attribute is not updated when interacting with the element.

Resources (screenshots, code snippets etc.)
none

Note
in docs aria-expanded is updated as expected when interacting with the element.