Add warning when you try to pass static params in "execute-command"

[gdubicki]

I tried to pass static params in "execute-command" like this:

"execute-command": "my_script.py some_static_param"

...instead of correctly doing it like this:

"execute-command": "my_script.py",
"pass-arguments-to-command": [ "source": "string", "name": "some_static_param" ]

It would be nice if webhook could provide tips with common/obvious problems in configuration such as this one.

In this case it could be triggered after detecting whitespace in "execute-command".

[adnanh]

I would gladly accept a good PR for this feature :-)

[adnanh]

Fixed in v2.6.6 by #164