[cairo] Builds failing on Gitlab CI

[Ayman El Didi]

Hello, I'm trying to contribute a couple commits I made (merge requests
278 and 279), and I noticed the CI keeps failing on the fedora autotools
build step with the error:

   failed to pull image 
"registry.freedesktop.org/aeldidi/cairo/fedora/34:2021-08-26.0" with 
specified policies [always]: Error response from daemon: manifest for 
registry.freedesktop.org/aeldidi/cairo/fedora/34:2021-08-26.0 not found 
(manager.go:203:0s)

I don't think this comes from my patches, since they don't affect the
build in any way. Does anyone know what could be causing this?