chore: Update stray serilog package reference in a test project (#3455)

Author: tippmar-nr

tests/Agent/UnitTests/NewRelic.Agent.TestUtilities/NewRelic.Agent.TestUtilities.csproj

@@ -14,7 +14,7 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="Serilog" Version="4.3.0" />
+    <PackageReference Include="Serilog" Version="4.3.1" />
     <PackageReference Include="Serilog.Sinks.Console" Version="6.1.1" />
     <PackageReference Include="Serilog.Sinks.Debug" Version="3.0.0" />
   </ItemGroup>