So it turns out that I was wrong and that .git/config is stateful. Multiple
calls to --add-provider will append the same provider each time...
Instead I'm defining secret-patterns.txt and version-controlling it.
Then:
- dev-side: I'm adding `providers = cat ci/secret-patterns.txt` to .git/config
- ci-side: I'm adding `providers = cat ci/secret-patterns.txt` to .git/config
Unfortunately this is ad-hoc configuration ci-side, which I would like to
avoid. The good news is that my pre-commit hooks and failures from git-secrets
should now align with my CI, since they're both reading from
secret-patterns.txt. One step backwards... two steps forwards?
