Run `ssh` command in quiet mode with `-q` (#35)
Run `ssh` command in quiet mode with `-q` (#35)

There are warning message like below when running a command in a Private sSpace:

```
heroku run bash -c 'echo 1' -a APP
Running bash -c "echo 1" on ⬢ APP… starting, run.3657 (Private-L)
 ▸    Warning: Dynos can take up to a few minutes to be provisioned in Private Spaces.
Warning: Permanently added '[127.0.0.1]:63639' (RSA) to the list of known hosts.
1
Connection to 127.0.0.1 closed.
```

This will suppress warning and diagnostic messages.
heroku/heroku-run,heroku/heroku-run