Is your feature request related to a problem? Please describe...

b-dropdown provides only variant as a way to set attributes and style on the b-button it creates

Describe the solution you'd like

Some way to set properties and attributes on the b-button that's created.

Describe alternatives you've considered

I have not found one which is why I'm filing this request.

Additional context

You need to make sure you don't generate markup and bootstrap components with no flexibility. I'm very concerned that this isn't the only case this plugin breaks or doesn't provide a way to actually use the flexibility of bootstrap itself.