[vulkan-headers] add git url (#2538)

packages/v/vulkan-headers/xmake.lua

@@ -4,6 +4,7 @@ package("vulkan-headers")
     set_description("Vulkan Header files and API registry")
     set_license("Apache-2.0")
 
+    add_urls("https://github.com/KhronosGroup/Vulkan-Headers.git")
     add_urls("https://github.com/KhronosGroup/Vulkan-Headers/archive/$(version).tar.gz", {version = function (version) return version:startswith("v") and version or "sdk-" .. version:gsub("%+", ".") end})
 
     -- when adding a new sdk version, please also update vulkan-loader, spirv-headers, glslang and volk packages