Create SECURITY.md

[34sin]

No description provided.

[sethcottle]

Hi @34sin, thanks for the PR. Not sure I see a real need to add a SECURITY.md, the project is just CSS and HTML. LittleLink doesn't rely on any dependencies—no frameworks, libraries, isn't pre-configured with URLs, ..etc. If there was any JS or anything remotely a bit more beyond the most vanilla and basic implementation of CSS and HTML, I could see it being a helpful addition—open to feedback though!