Update u_e-postfix-anonym_headers.md

docs/u_e-postfix-anonym_headers.md

@@ -1,7 +1,7 @@
 To disguise your users details like IP, email client, etc. we have to create a new file in `data/conf/postfix/mailcow_anonymize_headers.pcre` and insert the following:
 
 ```
-/^\s*Received:[^\)]+\)\s+\(Authenticated sender:(.+)/
+/^\s*Received:.*Authenticated sender:(.+)/
     REPLACE Received: from localhost (localhost [127.0.0.1]) (Authenticated sender:$1
 /^\s*User-Agent/        IGNORE
 /^\s*X-Enigmail/        IGNORE