chore(deps): update dependency microsoft.net.test.sdk to v18 (#62)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

src/Directory.Packages.props

@@ -11,7 +11,7 @@
   </PropertyGroup>
   <ItemGroup>
     <PackageVersion Include="Microsoft.AspNetCore.Components" Version="8.0.20" />
-    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />
     <PackageVersion Include="Microsoft.SourceLink.GitHub" Version="8.0.0" />
     <PackageVersion Include="Microsoft.Reactive.Testing" Version="$(RxVersion)" />
     <PackageVersion Include="Nerdbank.GitVersioning" Version="3.8.118" />