It is looking for the "shortnames" as specified in this document:
https://github.com/OrangeWulf/Rust-Docs/blob/master/Entities.md
So if you do a quick "ctrl-f" search for "autoturret" you will find the shortname "autoturret_deployed". The corresponding config snippet should look like this:
"Custom unprotected entities": [
"autoturret_deployed"
]
I haven't tested this with the auto turret specifically, so if it ends up not working just let me know, its possible auto turret is actually under a different name. Hope this helps though!