host style requires CSP with style-src 'unsafe-inline'

[jdanyow]

Is there another way to style the host as block without an inline style? Or could there be a mechanism for the host page to control the insertion of this style?

https://github.com/github/include-fragment-element/blob/75ac8d9978339004ec7fe4e73c121d64ccea6c3b/src/include-fragment-element.ts#L96-L98