Secret rotation

[HeikoMueller]

Hi... I have a question. In an earlier commet you mentioned that you'd add a way to rotate the secret by introducing old_secret:

https://github.com/patrickpissurno/fastify-esso/issues/2#issuecomment-620825433

I was unable to find this in the code. Has the idea of rotating secrets been implemented. If not, how would you approach this?

Thanks!

[HeikoMueller]

I added a pull request as a suggestion on how to tackle this: https://github.com/patrickpissurno/fastify-esso/pull/23