chore(deps): update dependency microsoft.net.test.sdk to v18

Author: renovate[bot]

src/directory.packages.props

@@ -26,7 +26,7 @@
     <PackageVersion Include="coverlet.msbuild" Version="6.0.4" />
     <PackageVersion Include="FluentAssertions" Version="8.8.0" />
     <PackageVersion Include="FluentAssertions.Analyzers" Version="0.34.1" />
-    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.0.0" />
     <PackageVersion Include="Microsoft.Reactive.Testing" Version="6.0.1" />
   </ItemGroup>
   <ItemGroup>