Update simdutf to v5.4.15 (#5080)

packages/s/simdutf/xmake.lua

@@ -6,6 +6,7 @@ package("simdutf")
     add_urls("https://github.com/simdutf/simdutf/archive/refs/tags/$(version).tar.gz",
              "https://github.com/simdutf/simdutf.git")
 
+    add_versions("v5.4.15", "188a9516ee208659cab9a1e5063c1b8385d63d171c2381e9ce18af97936d9879")
     add_versions("v5.3.11", "7926ae62d903a27452997e85d60c5dc04667d7a5ff44c2086ae90cf32bc4bc2c")
     add_versions("v5.3.4", "ccc9dab0c38bf0ee67374592707c6e6002148b99fb225a6b0c4604e90cfcbbc4")
     add_versions("v5.3.0", "9b568d6e66b14810bdbcf645f19b103475ab8175201b5c85828222c0ff0a735c")