[WIP] Use xUnit v3 through Microsoft Testing Platform

Does not work yet, see the tunit branch to adapt the tests csproj.

> Serilog.Formatting.Log4Net.Tests.csproj(46,5): error : ReportFiles is required

Author: 0xced

tests/Serilog.Formatting.Log4Net.Tests.csproj

@@ -2,24 +2,28 @@
 
   <PropertyGroup>
     <TargetFramework>net8.0</TargetFramework>
+    <OutputType>Exe</OutputType>
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>
     <PackageReference Include="AwesomeAssertions" Version="8.0.2" />
     <PackageReference Include="coverlet.collector" Version="6.0.4" PrivateAssets="all" />
     <PackageReference Include="GitHubActionsTestLogger" Version="2.4.1" PrivateAssets="all" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.13.0" />
     <PackageReference Include="PublicApiGenerator" Version="11.4.5" />
     <PackageReference Include="ReportGenerator" Version="5.4.5" PrivateAssets="all" />
     <PackageReference Include="Serilog" Version="4.2.0" />
     <PackageReference Include="Serilog.Enrichers.Environment" Version="3.0.1" />
     <PackageReference Include="Serilog.Enrichers.Thread" Version="4.0.0" />
     <PackageReference Include="Verify.XunitV3" Version="29.1.0" />
     <PackageReference Include="xunit.v3" Version="2.0.0" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="3.0.2" PrivateAssets="all" />
   </ItemGroup>
 
+  <PropertyGroup Label="xUnit">
+    <UseMicrosoftTestingPlatformRunner>true</UseMicrosoftTestingPlatformRunner>
+    <TestingPlatformDotnetTestSupport>true</TestingPlatformDotnetTestSupport>
+  </PropertyGroup>
+
   <ItemGroup>
     <VSTestLogger Include="GitHubActions%3Bsummary.includePassedTests=true%3Bsummary.includeSkippedTests=true" Visible="false" Condition="$(GITHUB_STEP_SUMMARY) != ''" />
     <VSTestLogger Include="trx%3BLogFileName=TestResults-$(TargetFramework).trx" Visible="false" Condition="$(ContinuousIntegrationBuild) == 'true'" />