gitlabci: Build and publish docs with gitlab pages.

.gitlab-ci.yml

@@ -1,6 +1,7 @@
 stages:
   - build
   - flatpak
+  - deploy
 
 .cache-paths: &cache-paths
   paths:
@@ -61,3 +62,21 @@ flatpak:widget-factory:
   variables:
     APPID: org.gtk.WidgetFactory
   <<: *flatpak-defaults
+
+pages:
+  image: registry.gitlab.gnome.org/gnome/gtk/master:v1
+  stage: deploy 
+  script:
+    - meson -Ddocumentation=true _build .
+    - ninja -C _build
+    - ninja -C _build gdk4-doc gsk4-doc gtk4-doc
+
+    - mkdir -p public/
+    - mv _build/docs/reference/gtk/html/ public/gtk/
+    - mv _build/docs/reference/gdk/html/ public/gdk/
+    - mv _build/docs/reference/gsk/html/ public/gsk/
+  artifacts:
+    paths:
+      - public
+  only:
+    - master