Add github topics to repo

[JohnMcSpedon]

I think it would increase the visibility of this repo to add Github topics. I was surprised when I didn't see this repo near the top of https://github.com/topics/image-labeling

Instructions for adding github topics: https://help.github.com/en/articles/classifying-your-repository-with-topics

example topics from opencv/cvat:

[nkrot]

it is better not to add topics, so that people are NOT able to find this obsolete, non maintained and close-to-death tool. it is barely worth investing an effort in trying it.