Simplify build dependencies

Author: jnyrup

Build/_build.csproj

@@ -7,24 +7,12 @@
     <NukeRootDirectory>..\</NukeRootDirectory>
     <NukeScriptDirectory>..\</NukeScriptDirectory>
   </PropertyGroup>
-  <PropertyGroup Condition="$([MSBuild]::IsOSPlatform('Windows'))">
-    <DefineConstants>OS_WINDOWS</DefineConstants>
-  </PropertyGroup>
-  <PropertyGroup Condition="$([MSBuild]::IsOSPlatform('Linux'))">
-    <DefineConstants>OS_LINUX</DefineConstants>
-  </PropertyGroup>
-  <PropertyGroup Condition="$([MSBuild]::IsOSPlatform('OSX'))">
-    <DefineConstants>OS_MAC</DefineConstants>
-  </PropertyGroup>
   <ItemGroup>
     <PackageDownload Include="GitVersion.Tool" Version="[5.12.0]" />
-    <PackageDownload Include="NSpec" Version="[3.1.0]" />
     <PackageDownload Include="ReportGenerator" Version="[5.1.23]" />
     <PackageDownload Include="xunit.runner.console" Version="[2.5.0]" />
-    <PackageDownload Include="Node.js.redist" Version="[16.20.0]" />
     <PackageReference Include="LibGit2Sharp" Version="0.27.2" />
     <PackageReference Include="Nuke.Common" Version="7.0.6" />
     <PackageReference Include="Nuke.Components" Version="7.0.6" />
-    <PackageDownload Include="Yarn.MSBuild" Version="[1.22.19]" />
   </ItemGroup>
 </Project>