Bump Serilog.Sinks.XUnit, Serilog and xunit.extensibility.core

Bumps [Serilog.Sinks.XUnit](https://github.com/trbenning/serilog-sinks-xunit), [Serilog](https://github.com/serilog/serilog) and [xunit.extensibility.core](https://github.com/xunit/xunit). These dependencies needed to be updated together.

Updates `Serilog.Sinks.XUnit` from 3.0.3 to 3.0.5
- [Release notes](https://github.com/trbenning/serilog-sinks-xunit/releases)
- [Commits](https://github.com/trbenning/serilog-sinks-xunit/commits)

Updates `Serilog` from 2.10.0 to 2.12.0
- [Release notes](https://github.com/serilog/serilog/releases)
- [Commits](serilog/serilog@v2.10.0...v2.12.0)

Updates `xunit.extensibility.core` from 2.4.1 to 2.4.2
- [Commits](xunit/xunit@2.4.1...2.4.2)

---
updated-dependencies:
- dependency-name: Serilog.Sinks.XUnit
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: Serilog
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: xunit.extensibility.core
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

.Lib9c.Tests/Lib9c.Tests.csproj

@@ -30,7 +30,7 @@
     <PackageReference Include="DiffPlex" Version="1.7.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.1.0" />
     <PackageReference Include="Serilog.Sinks.TestCorrelator" Version="3.2.0" />
-    <PackageReference Include="Serilog.Sinks.XUnit" Version="3.0.3" />
+    <PackageReference Include="Serilog.Sinks.XUnit" Version="3.0.5" />
     <PackageReference Include="Verify.Xunit" Version="17.2.1" />
     <PackageReference Include="xunit" Version="2.4.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3" />