Evaluate the possibility to remove the `docker` pipe from Loki custom values examle

In current Loki Stack custom values reference https://github.com/scalar-labs/helm-charts/blob/main/docs/conf/scalar-loki-stack-custom-values.yaml#L11, we use `docker` pipe.

From Kubernetes 1.26, it deprecates the Docker interface and use CRI only. Maybe we can remove this pipe and add `cri` instead then.

This issue is a note for the evaluation when 1.25 is out.