Well, I disagree. It doesn't matter where you store them, repo or not: even if they're not in a "repo", they're stored somewhere, and when you revoke access from someone to that somewhere, you still have the same problem: the party that you're revoking access from had access at one point. For all you know, they copied the secret while they had access. You can't "revoke" information from someone's mind: you MUST rotate the secret to accomplish that.

If anything, I like the git repo idea b/c — presuming that the repository stores a history of who had access to what, when — it removes the question of whether you need to rotate a secret. You can look at the history, and if the secret didn't get rotated when access was removed or at some time afterwards, you know you're not secure.

Compare that to say, a random file somewhere, say on a deployment node in deployment code, or alongside that code so as to keep it out of a repo, that just keeps the latest copy of the secrets, where one doesn't know when access was revoked. Do the keys need rotation?