force pseudo-tty allocation

Result: avoid `pseudo-terminal will not be allocated because stdin is not a terminal` error.

.gitlab/ci/ci.yml

@@ -69,6 +69,6 @@ production_deployment:
         - mkdir -p ~/.ssh
         - chmod 700 ~/.ssh
     script:
-        - ssh -A ubuntu@hifis-tp.desy.de
+        - ssh -A -tt ubuntu@hifis-tp.desy.de
         - echo $(whoami)
         - exit
\ No newline at end of file