update config to move out of beta phase

[zkamvar]

Congratulations @datacarpentry/r-socialsci-maintainers!

I have officially flipped the switch and your lesson will now serve from the workbench site by default.

This PR will remove the banner from the top and add the date created for the metadata.

[github-actions[bot]]

:ok: Pre-flight checks passed :smiley:

This pull request has been checked and contains no modified workflow files, spoofing, or invalid commits.

Results of any additional workflows will appear here when they are done.

[juanfung]

@zkamvar thank you! i was wondering if this was happening, very excited :)