Add impress.min.js to releases

[janishutz]

Okay. I think I cannot add anything to the releases, right?

Ah right. Can you file a new ticket and me or someone else could look into it in the future.

Originally posted by @henrikingo in #831 (comment)

Here we go.

[janishutz]

I'd also add this to the repo in general so one may use it with jsdelivr