chore: reduce redis-cluster pods and move HA out of "experimental" state (#565)

The pod reduction for `redis-cluster` should help users seeking for a Gitea deployment with less pods. Users seeking for a minimal deployment are further advised to follow https://gitea.com/gitea/helm-chart#user-content-single-pod-configurations.

HA is working fine in the provided configuration and should be moved out of the "experimental" state given that there were no reports of Gitea malfunctioning reported to HA usage in recent months/since v9 release.

Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/565
Reviewed-by: techknowlogick <[email protected]>
Co-authored-by: pat-s <[email protected]>
Co-committed-by: pat-s <[email protected]>

values.yaml

@@ -479,9 +479,14 @@ gitea:
 ## @section redis-cluster
 ## @param redis-cluster.enabled Enable redis
 ## @param redis-cluster.usePassword Whether to use password authentication
+## @param redis-cluster.cluster.nodes Number of redis cluster master nodes
+## @param redis-cluster.cluster.replicas Number of redis cluster master node replicas
 redis-cluster:
   enabled: true
   usePassword: false
+  cluster:
+    nodes: 3 # default: 6
+    replicas: 0 # default: 1
 
 ## @section postgresql-ha
 #