[receiver/k8s_cluster] move namespace to use pdata (#23437)

Switch k8s.namespace metrics to use pdata.

.chloggen/switchk8snamespace.yaml

@@ -0,0 +1,11 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: k8sclusterreceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Switch k8s.namespace metrics to use pdata.
+
+# One or more tracking issues related to the change
+issues: [23437]

receiver/k8sclusterreceiver/internal/collection/collector.go

@@ -108,7 +108,7 @@ func (dc *DataCollector) SyncMetrics(obj interface{}) {
 	case *corev1.Node:
 		md = ocsToMetrics(node.GetMetrics(o, dc.nodeConditionsToReport, dc.allocatableTypesToReport, dc.settings.TelemetrySettings.Logger))
 	case *corev1.Namespace:
-		md = ocsToMetrics(namespace.GetMetrics(o))
+		md = namespace.GetMetrics(dc.settings, o)
 	case *corev1.ReplicationController:
 		md = ocsToMetrics(replicationcontroller.GetMetrics(o))
 	case *corev1.ResourceQuota:

receiver/k8sclusterreceiver/internal/namespace/doc.go

@@ -0,0 +1,6 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+//go:generate mdatagen metadata.yaml
+
+package namespace // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/k8sclusterreceiver/internal/namespace"

receiver/k8sclusterreceiver/internal/namespace/documentation.md

@@ -0,0 +1,29 @@
+[comment]: <> (Code generated by mdatagen. DO NOT EDIT.)
+
+# k8s/namespace
+
+## Default Metrics
+
+The following metrics are emitted by default. Each of them can be disabled by applying the following configuration:
+
+```yaml
+metrics:
+  <metric_name>:
+    enabled: false
+```
+
+### k8s.namespace.phase
+
+The current phase of namespaces (1 for active and 0 for terminating)
+
+| Unit | Metric Type | Value Type |
+| ---- | ----------- | ---------- |
+| 1 | Gauge | Int |
+
+## Resource Attributes
+
+| Name | Description | Values | Enabled |
+| ---- | ----------- | ------ | ------- |
+| k8s.namespace.name | The k8s namespace name. | Any Str | true |
+| k8s.namespace.uid | The k8s namespace uid. | Any Str | true |
+| opencensus.resourcetype | The OpenCensus resource type. | Any Str | true |