Workaround for correct inclusion of SVG badges in docutils/reStrucutedText.

Docutils includes SVGs as <object> tags instead of <img>s because of some ancient IE issues (https://sourceforge.net/p/docutils/bugs/247/). The <object> behaves more or less like an iframe, so it collides with X-Frame-Options sent by Gitlab for badge URLs, resulting in the browser refusing to display the badge.

This is a workaround (from here) to fool it into using regular images.