try chmoding key

ci/push-package.template.yml

@@ -5,9 +5,8 @@
       - mkdir -p ~/.ssh
       - 'command -v ssh-agent >/dev/null || ( apt-get update -y && apt-get install openssh-client -y )'
       - eval $(ssh-agent -s)
-      - echo "$SSH_PRIVATE_KEY" | tr -d '\r' > ~/.ssh/id_ed25519
-      - chmod 400 ~/.ssh/id_ed25519
-      - ssh-add ~/.ssh/id_ed25519
+      - chmod 400 "$SSH_PRIVATE_KEY"
+      - ssh-add "$SSH_PRIVATE_KEY"
       - chmod 700 ~/.ssh
       - '[[ -f /.dockerenv ]] && echo -e "Host *\\n\\tStrictHostKeyChecking no\\n\\n" > ~/.ssh/config'
     script: