JSON workflow failing for PrintMessage Step

[abhiyad]

PrintMessage workflow fails with this error :
java.lang.RuntimeException: javax.script.ScriptException: :1:6 Expected ; but found 2.2
doing 2.2

The input json workflow looks like this
{
"id": "test-workflow",
"version": 1,
"dataType": "com.example.poc.WorkflowData",
"steps": [
{
"id": "print",
"stepType": "com.example.poc.PrintMessage",
"inputs": {
"message": "'doing 2.2'"
}
}
]
}