Update thorvg to v0.13.6 (#4208)

Author: waruqi

packages/t/thorvg/xmake.lua

@@ -6,6 +6,7 @@ package("thorvg")
     add_urls("https://github.com/thorvg/thorvg/archive/refs/tags/$(version).tar.gz",
              "https://github.com/thorvg/thorvg.git")
 
+    add_versions("v0.13.6", "f24fd3647e1a309dec00f6455b32258c0dd0e0dbd1133233169467571f188bad")
     add_versions("v0.13.5", "977ed74c3846c9a6acd5765aff776745d40e3c91507b22e51177d59c69afd198")
     add_versions("v0.13.2", "03b5dbb4c73ff221a4bd7243cc0ad377aecff4c3077f5a57ee2902e4122d3218")