Documentation on SECRETS is insufficient

[pboling]

We need examples of how to do a realistic set of secrets that are part of our build process.

For the PR Reivew Apps action this documentation exists here:
https://fly.io/docs/blueprints/review-apps-guide/#default-secrets-and-environment-variables

Please make it exist somewhere for the regular superfly/flyctl-actions/setup-flyctl action too.

[chopfitzroy]

@pboling you don't happen to know how to do this do you?

[pboling]

I did figure it out eventually. It was a bit tricky. I forgot about this issue, and I no longer have access to that project.

It is possible!!