TimeConversions do not implement getRecommendedSchema()

org.apache.avro.data.TimeConversions.TimestampConversion and other date and time conversions do not implement getRecommendedSchema(). When trying to dynamically generate an Avro schema from a pojo that contains a DateTime object using ReflectData, I get an unsupported operation exception.

I think the implementation should be as simple as

@Override
public Schema getRecommendedSchema() {
      return LogicalTypes.timestampMillis().addToSchema(Schema.create(Schema.Type.LONG));
}