Allow new Button component to support padding.

[Crateros]

Hello 👋
Really enjoying jsx-email, it has made handling our email templates a lot more manageable since I know very little about email specific HTML. I am in the process of migrating to V2 and noticed that the new component requires a set width and height. Previously I was using padding to accomplish the button dimensions, specifically the width, since we support translations in many languages so something help "Create a support ticket" would be varying lengths depending on the language being used. It would be great if the dimensions were optional or if padding was made available as a prop somehow.