docs(changelog): fix invalid context management scope

Change-Id: Ia94b944a023568fc53a812cefffe97a7b3af4266
Signed-off-by: Chris Kay <chris.kay@arm.com>
diff --git a/changelog.yaml b/changelog.yaml
index 8fcb217..fd48f8c 100644
--- a/changelog.yaml
+++ b/changelog.yaml
@@ -653,7 +653,10 @@
         scope: psa
 
       - title: Context Management
-        scope: context mgmt
+        scope: context-mgmt
+
+        deprecated:
+          - context mgmt
 
       - title: Semihosting
         scope: semihosting