Suppress security token deprecation warning for integration user.

[sprimeaux-nolapublicschools]

For integration users exempted from OAuth flow and multi-factor authentication, it might nice to have a way to suppress this warning:

"The security_token argument of sf_auth() is deprecated as of salesforcer 1.0.1."

I'm happy to work on this for you if you have a recommended approach.

[StevenMMortimer]

Thanks for flagging this was removed on the dev branch a couple years ago (0ddbc33) but never moved to the main branch and deployed to CRAN. I'll push this change into the next CRAN version.

Sorry for the delay.