check GRIB edtion

[perillaroc]

Check GRIB edition when create xarray.DataArray from GRIB message.

[perillaroc]

  # Hour (stepUnits.table)
  stepUnits = 1;
ECCODES ERROR   :  Unknown stepType=[51] timeRangeIndicator=[51]
  stepRange = ;  # *** ERR=-4 (Function not yet implemented) [grib_dumper_default::dump_string]
ECCODES ERROR   :  Unknown stepType=[51] timeRangeIndicator=[51]
  startStep = 0;
ECCODES ERROR   :  Unknown stepType=[51] timeRangeIndicator=[51]
  endStep = 0;
  #-READ ONLY- marsParam = 33.2;
  shortName = u;