chore: update NuGet packages

Author: jcdcdev

src/Umbraco.Community.BackOfficeOrganiser.TestSite/Umbraco.Community.BackOfficeOrganiser.TestSite.csproj

@@ -6,8 +6,8 @@
 	</PropertyGroup>
 
 	<ItemGroup>
-		<PackageReference Include="Umbraco.Cms" Version="[15.0.0,16.0.0)"/>
-		<PackageReference Include="uSync" Version="15.0.1"/>
+		<PackageReference Include="Umbraco.Cms" Version="15.3.1" />
+		<PackageReference Include="uSync" Version="15.1.6"/>
 	</ItemGroup>
 
 	<ItemGroup>