fix main project cpp version

Author: Inori

GPCS4/GPCS4.vcxproj

@@ -658,7 +658,7 @@
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <SDLCheck>true</SDLCheck>
       <ConformanceMode>true</ConformanceMode>
-      <LanguageStandard>stdcpplatest</LanguageStandard>
+      <LanguageStandard>stdcpp17</LanguageStandard>
       <BufferSecurityCheck>false</BufferSecurityCheck>
       <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
       <AdditionalIncludeDirectories>$(VULKAN_SDK)\Include;$(SolutionDir)GPCS4;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>