record marker failes because markerName is not added to recordMarkerDecisionAttributes

Hey guys,

when I try to record a marker I get an SWFResponseError:

```
SWFResponseError: SWFResponseError: 400 Bad Request
{'message': "1 validation error detected: Value null at 'decisions.1.member.recordMarkerDecisionAttributes.markerName' failed to satisfy constraint: Member must not be null", '__type': 'com.amazon.coral.validate#ValidationException'}
```

I already fixed it.

regards
Hannes