Setting the form-class on b-dropdown-form

[bbugh]

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

We have a b-dropdown-form that needs to be a flex-wrap: nowrap, among other settings. There is currently no way to set the class on the form of the b-form-dropdown. Using class="special-form" adds the class to the wrapper li.

Describe the solution you'd like

The common pattern in these scenarios seems to be having a new property that affects the specific component, like form-class.

Happy to PR this if it's an acceptable idea.

Describe alternatives you've considered

We could use a selector to say .special-form > form but that's getting into library implementation details.

Additional context

https://bootstrap-vue.org/docs/components/dropdown#comp-ref-b-dropdown-form-props

[tmorehouse]

The current workaround would be a custom style that targets the form element, but with scoped styles you would need the vue-loader deep selector:

<style scoped>
  .special-form /deep/ form {
    flex-wrap: nowrap;
  }
</style>

But a new prop form-class would allow you to place bootstrap utility classes on the form element.