build(changelog): add new scope for the threat model

Change-Id: I884f31f7f4b5515c420839ff37d401faa69f5fff
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
diff --git a/changelog.yaml b/changelog.yaml
index add81ef..cc81371 100644
--- a/changelog.yaml
+++ b/changelog.yaml
@@ -984,6 +984,9 @@
       - title: Prerequisites
         scope: prerequisites
 
+      - title: Threat Model
+        scope: threat-model
+
   - title: Build System
     scope: build