ci(.gitlab-ci): use Docker images for builds

.gitlab-ci.yml

@@ -3,6 +3,7 @@ image: python:3.13-slim
 
 stages:
   - prebuild
+  - pdf
   - build
   - deploy
   - deploy-pages
@@ -14,16 +15,27 @@ variables:
 
 prebuild:
   before_script:
-    - apt-get update && apt-get install -y pandoc python3-pip texlive-latex-base texlive-fonts-recommended texlive-fonts-extra texlive-latex-extra
+    - apt-get update && apt-get install -y python3-pip
     - python3 -m pip install poetry
-    - pandoc -v
     - poetry --version
   stage: prebuild
   script: |
     # Run the build script
     ./build.sh
-    echo "Generate Decks as PDF with Pandoc. It is generated as a backup."
-    pandoc -t beamer $PREBUILD_OUTPUT/fvv-folien-deck.md -o $PREBUILD_OUTPUT/fvv-folien.pdf
+  artifacts:
+    paths:
+      - $PREBUILD_OUTPUT
+    expire_in: "1 hour"
+
+pdf:
+  image: registry.gitlab.fachschaften.org/robinst/pandoc-image:latest
+  stage: pdf
+  dependencies:
+    - prebuild
+  script:
+    - echo "Generate Decks as PDF with Pandoc. It is generated as a backup."
+    - pandoc -t beamer $PREBUILD_OUTPUT/fvv-folien-deck.md -o $PREBUILD_OUTPUT/fvv-folien.pdf
+    - ls
   artifacts:
     paths:
       - $PREBUILD_OUTPUT