feat: refactor code for parallel execution on multiple hosts (#237)

- Update Dockerfile to use a newer version of `drone-ssh`
- Modify `ci.yml` to use `continue-on-error` instead of commenting out code

fix https://github.com/appleboy/ssh-action/issues/233

Dockerfile

@@ -1,4 +1,4 @@
-FROM appleboy/drone-ssh:1.6.10
+FROM ghcr.io/appleboy/drone-ssh:1.6.12
 
 COPY entrypoint.sh /entrypoint.sh
 RUN chmod +x /entrypoint.sh