Handling ssh-public-key

[stappersg]

Extending the example of creating an LXC container with ssh-public-keys yields the error
SyntaxError: keyword can't be an expression

I have a patch prepared for documenting how to handle ssh-public-keys.

In this issue I can tell more then in a commit message of the upcoming pull request.

First time I encounter the SyntaxError: keyword can't be an expression
I wrongly thought it was Python detecting an arithmetic operation.
So I tried to solve it outside the Python code, request rewrites with mitmproxy and even modifying the proxmox API code.

With my patch on README.rst I hope that others can easy use proxmoxer and SSH keys in the created container.

[swayf]

Thank you for PR :) it is merged, I will publish the new version this weekend