Update get_tokens.js

[MajorCallisto]

Changed callback to "oob" as per PIN-Based OAuth requirements: "The value for oauth_callback must be set to oob during the POST oauth/request_token call." - https://developer.twitter.com/en/docs/authentication/oauth-1-0a/pin-based-oauth (Feb 09, 2022)

Doing so redirects to PIN instead of callback url.

Also, thanks for this example - very helpful!