[msbuild] Transpile target should run if @(NESAssembly) files cha…

…nge (#61)

There was previously an incremental build bug:

1. `dotnet run`

2. Modify `chr_generic.s`

3. `dotnet run`

Your changes aren't there! You would need to run `dotnet clean` or
`dotnet build` to fix it.

src/dotnes.tasks/Targets/dotnes.targets

@@ -5,7 +5,7 @@
     <IncrementalCleanDependsOn>$(IncrementalCleanDependsOn);Transpile</IncrementalCleanDependsOn>
   </PropertyGroup>
   <Target Name="Transpile" AfterTargets="Build"
-      Inputs="$(TargetPath)" Outputs="$(NESTargetPath)">
+      Inputs="$(TargetPath);@(NESAssembly)" Outputs="$(NESTargetPath)">
     <TranspileToNES
         TargetPath="$(TargetPath)"
         AssemblyFiles="@(NESAssembly)"