Corrected the path casing for linux builders

source/SkiaSharp.Svg/SkiaSharp.Svg/SkiaSharp.Svg.csproj

@@ -37,7 +37,7 @@
   </PropertyGroup>
   <ItemGroup>
     <!-- A reference to the entire .NET Framework is automatically included -->
-    <ProjectReference Include="..\..\..\Binding\SkiaSharp.Portable\SkiaSharp.Portable.csproj">
+    <ProjectReference Include="..\..\..\binding\SkiaSharp.Portable\SkiaSharp.Portable.csproj">
       <Project>{7aa90628-2fdd-4585-af2f-cc51cfa8b52a}</Project>
       <Name>SkiaSharp.Portable</Name>
     </ProjectReference>

source/SkiaSharp.Views/SkiaSharp.Views.Desktop/SkiaSharp.Views.Desktop.csproj

@@ -61,7 +61,7 @@
     <None Include="packages.config" />
   </ItemGroup>
   <ItemGroup>
-    <ProjectReference Include="..\..\..\Binding\SkiaSharp.Desktop\SkiaSharp.Desktop.csproj">
+    <ProjectReference Include="..\..\..\binding\SkiaSharp.Desktop\SkiaSharp.Desktop.csproj">
       <Project>{eb1bbdcc-fb07-40d5-8b9e-0079e2c2f2df}</Project>
       <Name>SkiaSharp.Desktop</Name>
     </ProjectReference>