fix path to node_modules (#238)

Co-authored-by: Nik Erokhine <[email protected]>

Author: MicrosoftNik

src/windows/SliderWindows/SliderWindows.vcxproj

@@ -70,8 +70,11 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">
   </ImportGroup>
+  <PropertyGroup>
+    <ReactNativeWindowsDir Condition="'$(ReactNativeWindowsDir)' == ''">$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), 'node_modules\react-native-windows\package.json'))\node_modules\react-native-windows\</ReactNativeWindowsDir>
+  </PropertyGroup>
   <ImportGroup Label="Shared">
-    <Import Project="..\..\..\node_modules\react-native-windows\Microsoft.ReactNative.Cxx\Microsoft.ReactNative.Cxx.vcxitems" Label="Shared" />
+    <Import Project="$(ReactNativeWindowsDir)\Microsoft.ReactNative.Cxx\Microsoft.ReactNative.Cxx.vcxitems" Label="Shared" />
   </ImportGroup>
   <ImportGroup Label="PropertySheets">
     <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
@@ -153,7 +156,7 @@
     </Text>
   </ItemGroup>
   <ItemGroup>
-    <ProjectReference Include="..\..\..\node_modules\react-native-windows\Microsoft.ReactNative\Microsoft.ReactNative.vcxproj">
+    <ProjectReference Include="$(ReactNativeWindowsDir)\Microsoft.ReactNative\Microsoft.ReactNative.vcxproj">
       <Project>{f7d32bd0-2749-483e-9a0d-1635ef7e3136}</Project>
       <Private>false</Private>
     </ProjectReference>