docs(changelog): add 'dice' scope

To cover the DICE related works such as
DICE Protection Environment (DPE) integration
with the measurd boot framework.

Signed-off-by: Tamas Ban <tamas.ban@arm.com>
Change-Id: I9769b7bddbd1d269705ebff1d15870ab928fd8ef
diff --git a/changelog.yaml b/changelog.yaml
index 5696291..7f0c1ec 100644
--- a/changelog.yaml
+++ b/changelog.yaml
@@ -804,6 +804,9 @@
         deprecated:
           - lib/psa
 
+      - title: DICE Protection Environment
+        scope: dice
+
       - title: Context Management
         scope: context-mgmt