CLI: cannot set a file path to data in workflow.json

[josephjclark]

When running a workflow in the CLI, it is possible to set the expression (and I think credential) to a path.The CLI will then load this path when it loads the workflow.json.

This doesn't work for data at the moment, but it should. The data key sets the initial state for that step.

Example use-case:

{
    "workflow": {
        "steps": [
            {
                "id": "mapping",
                "adaptor": "common",
                "data": "./sampleData/data.json",
                "expression": "./jobs/parse-data.js"
            }
        ]
    }
}

Related: we may also want to support a state property on options, which would set the initial state if one isn't otherwise provided. This is probably a separate issue to be honest, but if I were working on it I would resolve both at once. I actually think the options thing is a more valuable use-case.