Update dependency Microsoft.NET.Test.Sdk to v18

Author: renovate[bot]

src/SignhostAPIClient.Tests/SignhostAPIClient.Tests.csproj

@@ -14,7 +14,7 @@
 		<PackageReference Include="FluentAssertions" Version="7.2.0" />
 		<PackageReference Include="RichardSzalay.MockHttp" Version="7.0.0" />
 		<PackageReference Include="xunit" Version="2.9.3" />
-		<PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
+		<PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.0" />
 		<PackageReference Include="xunit.runner.visualstudio" Version="3.1.5" />
 	</ItemGroup>