hardcode username for clarity (as it differs between docker.enterprisedb.com and helm.oci.cloudsmith.io)

Author: josh-heyer

product_docs/docs/klio/0/helm_chart.mdx

@@ -42,7 +42,6 @@ For simplicity, the instructions below assume you've put the following values in
 Example:
 
 ```sh
-export USERNAME=k8s
 export TOKEN=your-edb-token
 export NAMESPACE=cnpg-system
 ```
@@ -63,7 +62,7 @@ the registry:
 ```sh
 kubectl create secret docker-registry klio-registry-secret \
   --docker-server=docker.enterprisedb.com \
-  "--docker-username=${USERNAME}" \
+  "--docker-username=k8s" \
   "--docker-password=${TOKEN}" \
   "--namespace "${NAMESPACE}"
 ```