Merge pull request #45 from playgithub/add_versions_for_protobuf-cpp

add_versions 3.12.3 for protobuf-cpp

packages/p/protobuf-cpp/xmake.lua

@@ -5,6 +5,7 @@ package("protobuf-cpp")
 
     add_urls("https://github.com/protocolbuffers/protobuf/releases/download/v$(version)/protobuf-cpp-$(version).zip")
     add_versions("3.8.0", "91ea92a8c37825bd502d96af9054064694899c5c7ecea21b8d11b1b5e7e993b5")
+    add_versions("3.12.3", "74da289e0d0c24b2cb097f30fdc09fa30754175fd5ebb34fae4032c6d95d4ce3")
 
     if is_plat("windows") then
         add_deps("cmake")