Update dependency Microsoft.NET.Test.Sdk to 18.8.1

Author: renovate[bot]

test/DuckDB.EFCore.FunctionalTests/DuckDB.EFCore.FunctionalTests.csproj

@@ -34,7 +34,7 @@
     <PackageReference Include="Microsoft.EntityFrameworkCore.Relational.Specification.Tests" Version="10.0.9" />
     <PackageReference Include="Microsoft.Extensions.Configuration.EnvironmentVariables" Version="10.0.9" />
     <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="10.0.9" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.7.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.8.1" />
     <PackageReference Include="xunit.assert" Version="2.9.3" />
     <PackageReference Include="xunit.core" Version="2.9.3" />
     <PackageReference Include="xunit.extensibility.core" Version="2.9.3" />