Restart ssh service after updating the sshd configuration

[taicaile]

Hello, the service ssh start might be better changed to service ssh restart in case the ssh service already started.

https://github.com/WassimBenzarti/colab-ssh/blob/602f69fb25e12ff5119fcad4b6a536f16221b7ac/colab_ssh/launch_ssh_cloudflared.py#L56

to

 os.system('service ssh restart') 

[WassimBenzarti]

Hello again @taicaile :)

Thank you for filing this issue, I think this is very relevant. I will be creating a pull request as soon as possible.

Thank you for making colab-ssh amazing :)