Update NuGet packages

Use stable .NET 8 NuGet package versions.

Author: martincostello

Directory.Packages.props

@@ -1,6 +1,6 @@
 <Project>
   <PropertyGroup>
-    <MicrosoftExtensionsVersion>8.0.0-rc.2.23479.6</MicrosoftExtensionsVersion>
+    <MicrosoftExtensionsVersion>8.0.0</MicrosoftExtensionsVersion>
     <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
     <PollyVersion>8.1.0</PollyVersion>
   </PropertyGroup>
@@ -21,7 +21,7 @@
     <PackageVersion Include="Microsoft.Extensions.Logging.Console" Version="$(MicrosoftExtensionsVersion)" />
     <PackageVersion Include="Microsoft.Extensions.Options" Version="$(MicrosoftExtensionsVersion)" />
     <PackageVersion Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="$(MicrosoftExtensionsVersion)" />
-    <PackageVersion Include="Microsoft.Extensions.TimeProvider.Testing" Version="8.0.0-rc.2.23510.2" />
+    <PackageVersion Include="Microsoft.Extensions.TimeProvider.Testing" Version="8.0.0" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
     <PackageVersion Include="Microsoft.SourceLink.GitHub" Version="1.1.1" />
     <PackageVersion Include="MinVer" Version="4.3.0" />