Update firststeps-rp.md

it looks like the old version no longer works. no more redirection ... changed, tested and redirects now again

docs/firststeps-rp.md

@@ -50,7 +50,7 @@ Let's Encrypt will follow our rewrite, certificate requests in mailcow will work
   ServerAlias autoconfig.*
   RewriteEngine on
 
-  RewriteCond %{HTTPS} !=on
+  RewriteCond %{HTTPS} off
   RewriteRule ^/?(.*) https://%{HTTP_HOST}/$1 [R=301,L]
 
   ProxyPass / http://127.0.0.1:8080/