Add change log entry

Author: afarber

CHANGELOG.md

@@ -3,6 +3,7 @@
     - Build:
       - FIXED: Reduce MSVC compiler warnings by suppressing informational warnings while preserving bug-indicating warnings [#7253](https://github.com/Project-OSRM/osrm-backend/issues/7253)
     - Misc:
+      - CHANGED: Upgrade FlatBuffers to v25.9.23 with TypeScript workflow [#7235](https://github.com/Project-OSRM/osrm-backend/issues/7235)
       - CHANGED: Add std::format compatibility layer with fallback to fmt::format [#7261](https://github.com/Project-OSRM/osrm-backend/pull/7261)
       - FIXED: Update node_osrm to C++20 to fix ABI mismatch with libosrm (was overlooked in #6877) [#7261](https://github.com/Project-OSRM/osrm-backend/pull/7261)
       - CHANGED: Update fmt library to version 11.2.0 [#7238](https://github.com/Project-OSRM/osrm-backend/issues/7238)