Kranti, These vectors were generated using https://github.com/hanxiao/bert-as-service as I mentioned in the article in the section How are these vectors generated?.
Please remember to not use the CLS and SEP tag in vector generation.
There have been other methods that have come since I wrote this article which supposedly do better than this service. I havent tested them with same dataset to see if they perform better.
The paper https://arxiv.org/pdf/1908.10084.pdf
The code link