Created by: MartijnCuppens
Fixes https://github.com/twbs/bootstrap/issues/29426
Demo's:
- Normal card: https://deploy-preview-29453--twbs-bootstrap.netlify.com/docs/4.3/components/card/#example
- Accordion example: https://deploy-preview-29453--twbs-bootstrap.netlify.com/docs/4.3/components/collapse/#accordion-example
- One card accordion: https://codepen.io/MartijnCuppens/pen/QWLPJqK?editors=1000
- Issue fix: https://codepen.io/MartijnCuppens/pen/JjPVeOa?editors=1000