Add Statsig

[candicehchow]

https://statsig.com/

checklist

Please make sure you've complied with the contribution guidelines:

• [X ] The homepage clearly states that the product is for developers.

  "Headless", "API-First", "SaaS" are frequently used keywords. Usually this means that the front page has some code examples :)

• [ X] The product is available now and requires payment.
• [ X] The PR has a descriptive title -- e.g., Add {Product}, not Update README.md.
• [ X] The new submission isn't a duplicate.
• [ X] The entry has a description, is sorted alphabetically, and ends with a full stop.

Thanks!

[fmerian]

thanks for the suggestion, @candicehchow! please sort it alphabetically :)

any updates on this?