Fix csproj sdk casing issue

Case doesn't matter on windows but definitely does in unix.

src/MeidoPhotoStudio.Plugin/MeidoPhotoStudio.Plugin.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.Net.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
     <PropertyGroup>
         <TargetFramework>net35</TargetFramework>
         <LangVersion>9</LangVersion>