enable yaml-cpp on mingw (#484)

packages/y/yaml-cpp/xmake.lua

@@ -8,7 +8,7 @@ package("yaml-cpp")
     add_versions("0.6.3", "77ea1b90b3718aa0c324207cb29418f5bced2354c2e483a9523d98c3460af1ed")
 
     add_deps("cmake")
-    on_install("windows", "linux", "macosx", function (package)
+    on_install("windows", "linux", "macosx", "mingw", function (package)
         local configs = {"-DYAML_CPP_BUILD_TESTS=OFF"}
         table.insert(configs, "-DYAML_BUILD_SHARED_LIBS=" .. (package:config("shared") and "ON" or "OFF"))
         if package:is_plat("windows") then