text: Title: Unstable ETag because of hash rantomisation
  Body: Python `hash()` function is salted by default (see [__hash__](https://docs.python.org/3.8/reference/datamodel.html#object.__hash__) docs). Therefore the hash of the same object doesn't normally produce the same value in different processes.
  
  As a result, because of the way ETags are produced, the cache gets invalidated when the service restarts. Or, if the service is deployed with more than one backend behind a load balancer, every backend will return a different etag for the same resource, making it useless.
  
  https://github.com/long2ice/fastapi-cache/blob/91ba6d75524b1f6a17ae6a3300ab51b9aa1fcf71/fastapi_cache/decorator.py#L201
  
  As a workaround, setting `PYTHONHASHSEED` to a fixed value disables hash randomization.