Include component release notes in operator release notes

Problem

When a new Tekton Operator release is published, the release notes only cover changes made in the operator repository itself (features, fixes, misc). Users need to visit each component repository individually to understand what changed in the bundled components (Pipeline, Triggers, Chains, Dashboard, Results, etc.).

Since the operator is the primary installation mechanism for Tekton, most users only look at the operator release notes. They miss important changes — new features, deprecation notices, breaking changes, and bug fixes — from the bundled components.

Current State

The operator release (e.g. v0.79.0) lists:

• Operator-specific features, fixes, and misc changes
• Installation instructions and attestation info

It does not mention what changed in the bundled components, even though the payload includes specific versions of:

• Tekton Pipeline
• Tekton Triggers
• Tekton Chains
• Tekton Dashboard
• Tekton Results
• Pipelines as Code
• and others (see components.yaml)

Proposal

Add a "Component Updates" section to the operator release notes that includes, for each component whose version changed since the previous operator release:

1. Component name and version (old → new)
2. Link to the component's own release notes
3. Highlights — a curated summary of notable changes (features, breaking changes, deprecations)

Example

## Component Updates

### Tekton Pipeline: v1.9.0 → v1.10.2
[Full release notes](https://github.com/tektoncd/pipeline/releases/tag/v1.10.2)

**Highlights:**
- New feature X
- Deprecation of Y
- Bug fix for Z

### Tekton Triggers: v0.34.0 → v0.35.0
[Full release notes](https://github.com/tektoncd/triggers/releases/tag/v0.35.0)

**Highlights:**
- ...

Implementation Ideas

This could be automated as part of the release draft pipeline (release-draft-oci). The components.yaml file already tracks component versions, and comparing it with the previous release's components.yaml gives the diff. The GitHub API can fetch release notes for each component.

A script or Tekton Task could:

1. Diff components.yaml between the current and previous release tags
2. For each changed component, fetch release notes from the component's GitHub releases
3. Append a "Component Updates" section to the generated draft release notes

Alternatively, this could start as a manual step in the release cheat sheet and be automated later.

Start with components.yaml and the release-draft-oci pipeline, then read the release cheat sheet for the current release-note process. Compare the current and previous release component versions and determine how release notes can be fetched through the GitHub API. Done means the generated or documented release notes include changed components, old-to-new versions, links, and notable highlights.