Check if `sshpass` is available

[marcvs]

Withouth sshpass installed I get this error:

Usage: mccli [OPTIONS] COMMAND [ARGS]...

Error: No such command 'ssh-oidc-demo.data.kit.edu'.

Which makes sense, if you know the cause :)

Maybe adding a short "Prerequisites" section to installation.rst:

Prerequisites:
=============
Required dependencies:
- `sshpass`: This package is available on most linux distributions as `sshpass`
- `oidc-agent`: This package is available on most linux distributions as `oidc-agent` (use `oidc-agent-cli` on systems without GUI)

[dianagudu]

sshpass is not required by mccli, it is only an alternative to mccli, and --dry-run gives you the sshpass command after deploying the local account.

What command did you run to get this error?

It seems like you might be missing the ssh in mccli ssh ssh-oidc-demo.data.kit.edu.