try chmoding key

ci/push-package.template.yml

@@ -7,7 +7,7 @@
       - eval $(ssh-agent -s)
       - chmod 700 ~/.ssh
       - echo "$SSH_PRIVATE_KEY" | ssh-add - > ~/.ssh/id_rsa
-      - chmod 600 ~/.ssh/id_rsa
+      - chmod 400 ~/.ssh/id_rsa
       - '[[ -f /.dockerenv ]] && echo -e "Host *\\n\\tStrictHostKeyChecking no\\n\\n" > ~/.ssh/config'
     script:
       - mkdir -p /home/ssa/bin