Update changelogs for v0.21.5 release (#13618)

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
GitOrigin-RevId: 4e9ee93d282d28a31d9bf3c17dbde2b58a2ad45f

Author: kiryldz

CHANGELOG.md

@@ -31,6 +31,8 @@ Mapbox welcomes participation and contributions from everyone.
 
 * Fix old 3D puck model remaining after updating the puck model.
 
+## 11.21.5 - 15 May, 2026
+
 ## 11.21.4 - 05 May, 2026
 
 ## 11.21.3 - 23 April, 2026