message: Update security report doc for Tekton tasks and pipelines
diff: @@ -18,6 +18,10 @@ Artifact Hub will try to extract the containers images used by Helm charts from
  The images used by an OLM operator are extracted from the `containerImage` annotation in the [CSV file metadata section](https://github.com/operator-framework/community-operators/blob/master/docs/packaging-required-fields.md), as well as from the `related images` section in the CSV spec. Most of the OLM operators currently listed in Artifact Hub provide that information already, so security reports for them are already available in Artifact Hub with no extra effort required.
  +### Tekton tasks and pipelines
  +
  +The images used by Tekton tasks and pipelines are extracted from the [`task.step.image`](https://github.com/tektoncd/pipeline/blob/main/docs/tasks.md#running-scripts-within-steps) fields of the resource yaml file. If the `image` value is specified by [`params`](https://github.com/tektoncd/pipeline/blob/main/docs/tasks.md#specifying-parameters), the default value of the params (if provided) is used to run the security report. You can find examples with explanations [here](https://github.com/tektoncd/community/blob/main/teps/0079-tekton-catalog-support-tiers.md#extract-container-images-from-catalogs). Please note that the security reports do not include user-provided container images if the default value of the image `params` are overwritten by `pipelineRun` or `taskRun` at run time.
  +
  ### CoreDNS plugins, KEDA scalers, Keptn integrations, OPA policies and Tinkerbell actions
  Images used by these kinds of packages can be listed using the `containersImages` field in the package's `artifacthub-pkg.yml` [metadata file](https://github.com/artifacthub/hub/blob/master/docs/metadata/artifacthub-pkg.yml).
  