Volume binding detects github workspace

[errajibadr]

Hello

how do volumes work ?

volumes:
# allow traefik to monitor docker containers
  - /var/run/docker.sock:/var/run/docker.sock 
  - ./letsencrypt:/letsencrypt

i get this error :
"invalid mount config for type "bind": bind source path does not exist: /github/workspace/letsencrypt"