Hiya, we just did #GoToSocial bugfix release v0.18.1, which adds ETag cache control handling to /robots.txt to make it easier for crawlers to tell which instances they should + shouldn't be indexing.
You can find the release and update notes here:
https://github.com/superseriousbusiness/gotosocial/releases/tag/v0.18.1
If you're updating to this version from v0.18.0, it's a very easy update with no db migrations or config file changes :)
If you're updating to this version from a version before v0.18.0, please follow the update instructions from v0.18.0, but replace 0.18.0 with 0.18.1 throughout. Be aware that the update to 0.18.x contains some very long migrations. Please do read the notes carefully.
Thanks!