Add add_new_action_row method to DiscordResponse

[EthanC]

This is just a quality-of-life enhancement request.

DiscordResponse currently has an add_new_embed method that allows for a new Embed to be appended to the embeds property. Ideally, this API could be reimplemented for the ActionRow object and action_rows property.

Example

res: DiscordResponse = DiscordResponse(...)

res.add_new_action_row(ActionRow(...))

[ms7m]

This sounds good. This will be added in the next release.