Adds links to changelog in HTML

- adds links to `2.1/changelog.html` in each HTML spec
- includes summary of changes (additions/removals) for each spec

2.1/ai/ai-en.html

@@ -20097,7 +20097,19 @@ <h3>Funding Acknowledgements for Contributors</h3>
 
 <section id="changelog">
   <h2>Changelog for v2.1</h2>
-  <div class="issue" title="Changelog for v2.1"></div>
+  <p><strong>total terms: 208 ; added: 192 ; removed: 1 ;</strong></p>
+  <p>The <a href="../changelog.html">changelog</a> provides more information on concepts that have been added/removed in this version. Below is a summary of the changes.</p>
+  <ul>
+    <li><code>Risk</code> was renamed to <code>RiskConcept</code> as a specialisation of DPV's concept to enable it to be used in multiple roles as detailed in the <code>RISK</code> extension.</li>
+    <li>Integrates concepts from <a href="https://w3id.org/airo"><code>AI Risk Ontology (AIRO)</code></a> by Golpayegani et al.</li>
+    <li>Integrates concepts from <a href="https://w3id.org/vair"><code>Vocabulary of AI Risks (VAIR)</code></a> by Golpayegani et al.</li>
+    <li>Added concepts for <code>Technique</code>.</li>
+    <li>Added concepts for <code>Capability</code>.</li>
+    <li>Added concepts for <code>AISystem</code> and <code>Model</code>.</li>
+    <li>Added concepts for <code>Data</code> including training, output, and validation.</li>
+    <li>Added <code>RiskConcept</code> taxonomies to represent concepts that can be risk sources, risks, consequences, impacts - including <code>DataRisk</code> and <code>AIBias</code>.</li>
+    <li>Added concepts for <code>LifecycleStage</code> based on ISO/IEC 22989:2022.</li>
+  </ul>
 </section>
 
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