chore: Add note about version tag to README (#69)

README.md

@@ -19,6 +19,7 @@ $ helm install --create-namespace --namespace immich immich immich/immich -f val
 There are a few things that you are required to configure in your values.yaml before installing the chart:
 * You need to separately create a PVC for your library volume and configure `immich.persistence.library.existingClaim` to reference that PVC
 * You need to make sure that Immich has access to a redis, postgresql, and typesense instance. You can do this either by enabling them directly in the values.yaml, or by manually setting the entries under the `env` key to point to existing instances.
+* You need to set `image.tag` to the version you want to use, as this chart does not update with every Immich release.
 
 # Configuration