How to copy files in current GitLab runner's directory to remote server?

Using Self-Managed GitLab server and docker executor installed on the external GitLab runner.

I have a file ‘docker-compose.yml’ store in the project directory and I want to copy this file and paste to the remote server in order to call the docker stack deploy -c docker-compose.yml.

I’ve set a ssh session and able to login to the remote server.
The thing that I think I’ll do next is perform scp command at the remote server back to the Gitlab runner. But this will mess thing up. I have to deal with the credentials and permissions of GitLab runner which I don’t have a root access. So, I can’t enter to the project directory.

Any alternative ways for this?