add digestpp (#2918)

* add digestpp

* Update xmake.lua

---------

Co-authored-by: Your Name <you@example.com>

packages/d/digestpp/xmake.lua

@@ -0,0 +1,22 @@
+package("digestpp")
+    set_kind("library", {headeronly = true})
+    set_homepage("https://github.com/kerukuro/digestpp")
+    set_description("C++11 header-only message digest library")
+    set_license("MIT")
+
+    add_urls("https://github.com/kerukuro/digestpp.git")
+    add_versions("2023.11.8", "ebb699402c244e22c3aff61d2239bcb2e87b8ef8")
+
+    on_install(function (package)
+        os.cp("*", package:installdir("include"))
+    end)
+
+    on_test(function (package)
+        assert(package:check_cxxsnippets({test = [[
+            #include <iostream>
+            #include "digestpp.hpp"
+            void test() {
+                std::cout << digestpp::blake2b().absorb("The quick brown fox jumps over the lazy dog").hexdigest();
+            }
+        ]]}, {configs = {languages = "c++17"}}))
+    end)