Install openssh on CI

.gitlab-ci.yml

@@ -26,7 +26,7 @@ doxygen:
   tags:
     - documentation
   before_script:
-    - apk update && apk --no-cache add git doxygen graphviz ttf-freefont texmf-dist texmf-dist-latexextra texlive texlive-dvi
+    - apk update && apk --no-cache add git doxygen graphviz ttf-freefont texmf-dist texmf-dist-latexextra texlive texlive-dvi openssh
   script:
     # aircraft design
     - git clone --recurse-submodules https://gitlab-ci-token:${CI_JOB_TOKEN}@git.rwth-aachen.de/unicado/aircraft-design