Support Umbraco 16.0.0-rc4

Author: rickbutterfield

src/Umbraco.Community.Sustainability.TestSite.16.x/Umbraco.Community.Sustainability.TestSite.16.x.csproj

@@ -7,7 +7,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Umbraco.Cms" Version="16.0.0-rc3" />
+    <PackageReference Include="Umbraco.Cms" Version="16.0.0-rc4" />
     <PackageReference Include="Umbraco.TheStarterKit" Version="16.0.0-rc" />
   </ItemGroup>