Add self-heal for manually modified secrets

[jonathan-a-you]

Hello,

This request is about sealed-secrets-controller version v0.24.0.

I'm using sealed-secrets with argo cd, and argo cd is able to see any differences on the sealed secrets and heal them automatically. But the sealed-secrets-controller doesn't watch differences on the secret, so if someone modify a secret in the UI, there will be a mismatch between my sealed secret and my secret.

I would like to make sure my secret value matches the source of truth, which is GitHub.

Currently, sealed-secrets-controller watches secret deletion and is able to re-create them.
It would be great if it could also watch unsynced secrets and heal them automatically if there is a difference.

Thank you so much!