gitlab-ci: Use v2022 documentation-builder image

The previous URL no longer even functions, and v2022 is quite outdated
regardless.

https://phabricator.apertis.org/T9237



Signed-off-by: Ryan Gonzalez <ryan.gonzalez@collabora.com>

.gitlab-ci.yml

@@ -54,7 +54,7 @@ test-html:
     - public
 
 .gen-pdf:
-  image: docker-registry.apertis.org/apertis/apertis-v2020-documentation-builder
+  image: registry.gitlab.apertis.org/infrastructure/apertis-docker-images/v2022-documentation-builder
   stage: generate-pdf
   tags:
     - lightweight