CoreMIDI watchOS 8.0 Beta 3 to Beta 4 API Differences

MIDIMessages.h
Removed kMIDISysExMixedDataSetHeader
Removed kMIDISysExMixedDataSetPayload
Removed MIDINoteAttributeType
Added kMIDISysExStatusMixedDataSetHeader
Added kMIDISysExStatusMixedDataSetPayload
Added MIDINoteAttribute