K8s: Simplify the update REC credential step

[kaitlynmichael]

Jira: DOC-4813

[github-actions]

Staging links:
https://redis.io/docs/staging/DOC-4813/operate/kubernetes/security/manage-rec-credentials

[dwdougherty]

LGTM (after reading some K8s docs)

[markotrapani]

Looks good! Only suggestion is that we clarify the differences in the credentials used in kubectl between the two sections

Change the REC password for the current username

kubectl create secret generic <cluster_secret_name> \
  --save-config \
  --dry-run=client \
  --from-literal=username=<current_username> \
  --from-literal=password=<new_password> \
  -o yaml | \
kubectl apply -f - 

Change both the REC username and password

kubectl create secret generic <cluster_secret_name> \
  --save-config \
  --dry-run=client \
  --from-literal=username=<new_username> \
  --from-literal=password=<new_password> \
  -o yaml | \
kubectl apply -f - 

[yuvallevy2]

@kaitlynmichael I am assuming you are testing the new steps, correct?

[zcahana]

LGTM!