ci: documentation build bot uses an old docker fedora image
documentation build bot uses an old docker fedora image:
Using Docker executor with image registry.freedesktop.org/gstreamer/gst-ci/amd64/fedora:2020-07-03.0-master ...
The problem is it has and old version of libva-dev which isn't supported by gstva, so gstva library isn't generated and neither its documentation. Then, if plugins (read by plugins_cache.json) use API documented in gstva library, documentation will fail.
What would be the procedure to update docker's image used by documentation build bot?