Update .gitlab-ci.yml file

.gitlab-ci.yml

@@ -19,13 +19,14 @@ stages:
   - build
   - deploy
 
+# === Build the doxygen documentation ===
 doxygen:
   image: alpine:latest
   stage: build
   tags:
     - documentation
   before_script:
-    - apk update && apk --no-cache add git doxygen graphviz
+    - apk update && apk --no-cache add git doxygen graphviz ttf-freefont texlive
   script:
     - git clone -b feature-aircraftGeometry2 --recurse-submodules https://gitlab-ci-token:${CI_JOB_TOKEN}@git.rwth-aachen.de/unicado/libraries
     - cd libraries/aircraftGeometry2/doc/ && ( cat Doxyfile ; echo "OUTPUT_DIRECTORY = $CI_PROJECT_DIR/docs/modules/" ) | doxygen -
@@ -38,6 +39,7 @@ doxygen:
     - if: '$CI_COMMIT_BRANCH != $CI_DEFAULT_BRANCH'
       when: manual
 
+# === Build and deploy the website ===
 pages:
   image: python:latest
   stage: deploy