grafana loki helm chart default values with oss/overrides-oss-gcs.yaml install field fail

[JaneLiuL]

Describe the bug
Apply loki helm chart docs/example/oss/overrides-oss-gcs.yaml values when helm install
loki pod will fail as below

failed parsing config: /etc/loki/config/config.yaml: yaml: unmarshal errors:
  line 33: field bucketNames not found in type gcp.GCSConfig
  line 77: field bucketNames not found in type gcp.GCSConfig
  line 97: field retention not found in type config.plain. Use `-config.expand-env=true` flag if you want to expand environment variables in your config file

To Reproduce
Steps to reproduce the behavior:
0. helm pull grafana/loki

1. tar zxf chart
2. helm -n loki-stack upgrade --install loki ./ -f ./docs/examples/oss/overrides-oss-gcs.yaml

Expected behavior
A clear and concise description of what you expected to happen.

Environment:

• Infrastructure: [e.g., Kubernetes, bare-metal, laptop] gke
• Deployment tool: [e.g., helm, jsonnet] helm

Screenshots, Promtail config, or terminal output
If applicable, add any output to help explain your problem.