Update cgltf to v1.15 (#6356)

packages/c/cgltf/xmake.lua

@@ -6,6 +6,7 @@ package("cgltf")
 
     add_urls("https://github.com/jkuhlmann/cgltf/archive/refs/tags/$(version).tar.gz",
              "https://github.com/jkuhlmann/cgltf.git")
+    add_versions("v1.15", "84e352092e5cd6aab7f66de62ddb66beb5e6f18d412ca9d12950d7a55bfef25a")
     add_versions("v1.14", "2f3c97a6b989943f50e7d7f228688f6558fe37b1411c13a350e3560d061707d8")
     add_versions("v1.13", "053d5320097334767486c6e33d01dd1b1c6224eac82aac2d720f4ec456d8c50b")