Bump Microsoft.NET.Test.Sdk from 18.5.1 to 18.6.0

---
updated-dependencies:
- dependency-name: Microsoft.NET.Test.Sdk
  dependency-version: 18.6.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: Microsoft.NET.Test.Sdk
  dependency-version: 18.6.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

test/LibYear.Core.Tests/LibYear.Core.Tests.csproj

@@ -6,7 +6,7 @@
 	</PropertyGroup>
 	<ItemGroup>
 		<PackageReference Include="coverlet.collector" Version="10.0.1" />
-		<PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.5.1" />
+		<PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.6.0" />
 		<PackageReference Include="NSubstitute" Version="5.3.0" />
 		<PackageReference Include="xunit" Version="2.9.3" />
 		<PackageReference Include="xunit.runner.visualstudio" Version="3.1.5" />

test/LibYear.Tests/LibYear.Tests.csproj

@@ -6,7 +6,7 @@
 	</PropertyGroup>
 	<ItemGroup>
 		<PackageReference Include="coverlet.collector" Version="10.0.1" />
-		<PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.5.1" />
+		<PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.6.0" />
 		<PackageReference Include="Spectre.Console.Testing" Version="0.55.2" />
 		<ProjectReference Include="..\..\src\LibYear\LibYear.csproj" />
 		<ProjectReference Include="..\LibYear.Core.Tests\LibYear.Core.Tests.csproj" />