Update CHANGES_NEXT_RELEASE

Author: AlvaroVega

CHANGES_NEXT_RELEASE

@@ -1,6 +1,6 @@
 - Add: /iot/groups API endpoints support (as equivalent to /iot/services) (#270)
 - Deprecated: /iot/services API routes
 - Upgrade body-parser dep from 1.19.0 to 1.20.3
-- Upgrade express from 4.19.2 to 4.20.0
+- Upgrade express from 4.19.2 to 4.21.2
 - Upgrade mongodb devdep from 4.17.0 to 4.17.2
 - Upgrade mongoose dep from 5.13.20 to 8.8.4 (solving vulnerability CVE-2024-53900) (#351)