Only install openssh-client, not entire ssh package

.gitlab-ci.yml

@@ -34,7 +34,7 @@ deploy-apt:
     paths:
       - build-stretch
   script:
-    - apt-get update && apt-get install ssh -y
+    - apt-get update && apt-get install openssh-client -y
     - (
         umask 077;
         mkdir -p ~/.ssh;