Merge pull request #141 from serilog-contrib/dependabot/nuget/xunit-2.5.1

Bump xunit from 2.4.2 to 2.5.1

Author: 0xced

tests/Serilog.Formatting.Log4Net.Tests.csproj

@@ -17,7 +17,7 @@
     <PackageReference Include="Serilog.Enrichers.Environment" Version="2.2.0" />
     <PackageReference Include="Serilog.Enrichers.Thread" Version="3.1.0" />
     <PackageReference Include="Verify.Xunit" Version="20.3.2" />
-    <PackageReference Include="xunit" Version="2.4.2" />
+    <PackageReference Include="xunit" Version="2.5.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5" PrivateAssets="all" />
   </ItemGroup>