pipeline: filters: kubernetes: add use_tag_for_meta config param

pipeline/filters/kubernetes.md

@@ -51,6 +51,7 @@ The plugin supports the following configuration parameters:
 | DNS\_Retries | DNS lookup retries N times until the network start working | 6 |
 | DNS\_Wait\_Time | DNS lookup interval between network status checks | 30 |
 | Use\_Kubelet | this is an optional feature flag to get metadata information from kubelet instead of calling Kube Server API to enhance the log. This could mitigate the [Kube API heavy traffic issue for large cluster](kubernetes.md#optional-feature-using-kubelet-to-get-metadata). If used when any [Kubernetes Namespace Meta](#kubernetes-namespace-meta) fields are enabled, Kubelet will be used to fetch pod data, but namespace meta will still be fetched using the `Kube_URL` settings.| Off |
+| Use\_Tag\_For\_Meta | When enabled, Kubernetes metadata (e.g., pod_name, container_name, namespace_name etc) will be extracted from the tag itself. Connection to Kubernetes API Server will not get established and API calls for metadata won't be made. See [Workflow of Tail + Kubernetes Filter](#workflow-of-tail--kubernetes-filter) and [Custom Tag For Enhanced Filtering](#custom-tag-for-enhanced-filtering) to better understand metadata extraction from tags. | Off |
 | Kubelet\_Port | kubelet port using for HTTP request, this only works when `Use_Kubelet`  set to On. | 10250 |
 | Kubelet\_Host | kubelet host using for HTTP request, this only works when `Use_Kubelet`  set to On. | 127.0.0.1 |
 | Kube\_Meta\_Cache\_TTL | configurable TTL for K8s cached pod metadata. By default, it is set to 0 which means TTL for cache entries is disabled and cache entries are evicted at random when capacity is reached. In order to enable this option, you should set the number to a time interval. For example, set this value to 60 or 60s and cache entries which have been created more than 60s will be evicted. | 0 |