change-log: Add fconf entry

Change-Id: I6686f172d0c24f6c457a39cdf4debcbf05475540
Signed-off-by: Louis Mayencourt <louis.mayencourt@arm.com>

docs/change-log-upcoming.rst

@@ -33,6 +33,7 @@ New Features
 
 - Libraries
    - Example: "Introduce BTI support in Library at ROM (romlib)"
+   - Add Firmware Configuration Framework (fconf).
 
 - New Platforms Support
    - Example: "qemu/qemu_sbsa: New platform support added for QEMU SBSA platform"