Migrate to Asciinema player V3 #57
Description
https://docs.asciinema.org/manual/player/upgrading/#upgrading-from-v2-to-v3
The V2 player we use is based on a deprecated API. We should upgrade to the V3 way which is a <script> tag calling Asciinema functions.
Hopefully this should be as simple as upgrading the JavaScript file and the shortcode: templates/shortcodes/asciinema.html.