Message box input press `Enter` to confirm

Vue: `v2.6.12`  
BootstrapVue: `v2.21.2`

Instead of manually clicking `OK`, how to press `Enter` to confirm?

```js
let text
this.$bvModal.msgBoxConfirm(<input vModel={text} />)
```

![image](https://user-images.githubusercontent.com/28700378/112244619-7c141b00-8c8a-11eb-9bde-0156984eaac3.png)

