Update dependency Microsoft.Testing.Extensions.CodeCoverage to v18

Author: renovate[bot]

Directory.Packages.props

@@ -24,7 +24,7 @@
         <GlobalPackageReference Include="JetBrains.Annotations.Sources" Version="2026.2.0" Condition="$(MSBuildProjectName) != '.build'" />
     </ItemGroup>
     <ItemGroup>
-        <PackageVersion Include="Microsoft.Testing.Extensions.CodeCoverage" Version="17.14.2" />
+        <PackageVersion Include="Microsoft.Testing.Extensions.CodeCoverage" Version="18.8.0" />
         <PackageVersion Include="Microsoft.Testing.Extensions.TrxReport" Version="1.9.1" />
         <PackageVersion Include="Rocket.Surgery.ModularPipelines.Extensions" Version="0.1.4" />
         <PackageVersion Include="Sourcy.DotNet" Version="1.1.1" />