Update GithubToken for dataset requests

[davidsmejia]

Context:

Github has changed the format for their tokens. We need to issue a new token and update it in the env vars on vercel. AFAIK this does not require any code changes.

Relevant code here:
https://github.com/AlexsLemonade/refinebio-frontend/blob/dev/src/common/github.js#L10
More information here:
https://github.blog/2021-04-05-behind-githubs-new-authentication-token-formats/