Specify headers

[martinlundhgren]

Is it possible to specify headers in a request? The external API won't accept requests without a specific header set.

[Dedac]

It isn't currently, you can see in rest-call
that the parameters are hard coded to expecting a JSON result.
It wouldn't be a huge lift to add another input matching RestCallParameters named RestCallHeaders and do the same thing. Would you like to do a PR?