Documentation says labels start at 1 instead of 0

Prerequisites

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1. The entire URL of the documentation with the issue

https://github.com/tensorflow/models/blob/master/research/object_detection/g3doc/using_your_own_dataset.md

2. Describe the issue

A clear and concise description of what needs to be changed.

A stackoverflow user noticed on this page for setting class label IDs, it say they should start at the value 1. They should start at 0.

Label Maps
Each dataset is required to have a label map associated with it. This label map defines a mapping from string class names to integer class Ids. The label map should be a StringIntLabelMap text protobuf. Sample label maps can be found in object_detection/data. Label maps should always start from id 1.