Describe the feature that you would like added

Allowing the developer to choose the buttons tag.

What component or utility would this be added to

DefaultButton, PrimaryButton

Have you discussed this feature with our team, and if so, who

No

Additional context/screenshots

Currently buttons renders as button or a (if href prop is defined). Sometimes it needed to be set as different type like span. Like when the button should act like a label, for example:

<input
  className={classes.displayNone}
  id='upload-button-file'
  type='file'
  />
<label htmlFor='upload-button-file'>
  <DefaultButton>Upload</DefaultButton>
</label>