added note to configure KUBERNETES_RUN_AS_USER & KUBERNETES_RUN_AS_GROUP for native k8s executors

Author: loujar

docs/admin/executors/deploy_executors_kubernetes.mdx

@@ -27,6 +27,7 @@ Native Kubernetes Executors can be deployed via either the `sourcegraph-executor
     2. `EXECUTOR_FRONTEND_PASSWORD` should match the `executors.accessToken` key in the Sourcegraph instance's site configuration
     3. Either `EXECUTOR_QUEUE_NAMES` or `EXECUTOR_QUEUE_NAME` should be set depending on whether the Executor will process batch change or precise auto indexing jobs
     4. `EXECUTOR_KUBERNETES_NAMESPACE` should be set to the Kubernetes namespace where you intend to run the worker pods. This should generally match the namesapce where you deploy the Executor resources in the next step.
+    5. `KUBERNETES_RUN_AS_USER` and `KUBERNETES_RUN_AS_GROUP` should be set to the user and group IDs that the worker pods should run as.
 
     <Callout type="note">Additional environment variables may need to be configured for your Executors deployment. See [here](/admin/executors/executors_config) for a complete list.</Callout>