let's try this again...

ci/push-package.template.yml

@@ -3,11 +3,11 @@
     image: python:3.10-slim
     before_script:
       - mkdir -p ~/.ssh
-      - 'which ssh-agent || ( apt-get update -y && apt-get install openssh-client -y )'
+      - 'command -v ssh-agent >/dev/null || ( apt-get update -y && apt-get install openssh-client -y )'
       - eval $(ssh-agent -s)
+      - chmod 400 "$SSH_PRIVATE_KEY"
+      - ssh-add "$SSH_PRIVATE_KEY"
       - chmod 700 ~/.ssh
-      - echo "$SSH_PRIVATE_KEY" | tr -d '\r' | ssh-add - > ~/.ssh/id_rsa
-      - chmod 600 ~/.ssh/id_rsa
       - '[[ -f /.dockerenv ]] && echo -e "Host *\\n\\tStrictHostKeyChecking no\\n\\n" > ~/.ssh/config'
     script:
       - mkdir -p /home/ssa/bin