Extract container.image.tag attribute from container.image.name

Update k8sClusterReceiver component to export `container.image.tag` attribute from `container.image.name` according to OpenTelemetry semantic conventions https://github.com/open-telemetry/opentelemetry-specification/blob/v1.8.0/specification/resource/semantic_conventions/container.md

This can be removed once this issue open-telemetry/opentelemetry-collector-contrib#6314 is resolved

CHANGELOG.md

@@ -8,6 +8,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 - Field name compatibility for SCK (#258)
 
+### Changed
+
+- Extract `container.image.tag` attribute from `container.image.name` (#285)
+
 ### Removed
 
 - Busybox image dependency (#275)

helm-charts/splunk-otel-collector/templates/config/_otel-k8s-cluster-receiver-config.tpl

@@ -94,6 +94,21 @@ processors:
         key: {{ .name }}
         value: {{ .value }}
       {{- end }}
+      # Extract "container.image.tag" attribute from "container.image.name" here until k8scluster 
+      # receiver does it natively.
+      - key: container.image.name
+        pattern: ^(?P<container_image_name>[^\:]+)(?:\:(?P<container_image_tag>.*))?
+        action: extract
+      - key: container.image.name
+        from_attribute: container_image_name
+        action: upsert
+      - key: container_image_name
+        action: delete
+      - key: container.image.tag
+        from_attribute: container_image_tag
+        action: upsert
+      - key: container_image_tag
+        action: delete
 
 exporters:
   {{- if eq (include "splunk-otel-collector.o11yMetricsEnabled" $) "true" }}