Actually fix letsencrypt issue.

README.md

@@ -309,6 +309,9 @@ and sign out at `https://<any-app>/_google-auth/logout`.
   `location /foo` prefix blocks will be shadowed by this plugin's catch-all
   regex location — use `location ^~ /foo` in your own snippets if you need
   them to win.
+- **dokku-letsencrypt HTTP-01 renewals** keep working: the catch-all skips
+  `/.well-known/acme-challenge/`, so the challenge location letsencrypt
+  writes during a renewal is served without a Google session.
 - **Non-browser clients** (curl, fetch without `Accept: text/html`) get a
   JSON `401` instead of a redirect chain.
 - **Websockets** work — upgrade headers are forwarded exactly like dokku's