SpiceDB is an open source, Google Zanzibar-inspired, database system for creating and managing security-critical application permissions.

SpiceDB

How to enable expiration trait in spicedb?

I am getting the error
```
expiration trait is not allowed
```

when trying to add `expiration` to the schema

```
use expiration

definition simple {
  relation viewer: user with expiration
}
```

SpiceDB version: v1.39.1

```
 ~ zed version
client: zed v0.21.5
service: v1.39.1
```

There is no `enable-experimental-relationship-expiration` option in `spicedb serve`.