Bump SampleServer's Microsoft.Extensions.Logging package

In order to allow it to restore since this dependency was updated
upstream, and that was causing it to fail to restore due to the detected
forced downgrade.

Author: andyleejordan

sample/SampleServer/SampleServer.csproj

@@ -10,7 +10,7 @@
 
     <ItemGroup>
         <ProjectReference Include="../../src/Server/Server.csproj" />
-        <PackageReference Include="Microsoft.Extensions.Logging" VersionOverride="3.0.0" />
+        <PackageReference Include="Microsoft.Extensions.Logging" VersionOverride="6.0.0" />
         <PackageReference Include="Serilog.Extensions.Logging" VersionOverride="3.1.0" />
         <PackageReference Include="Serilog.Sinks.File" VersionOverride="5.0.0" />
         <PackageReference Include="Serilog.Sinks.Debug" VersionOverride="2.0.0" />