Bump xunit.runner.visualstudio to 3.1.2 (#164)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

tests/Prometheus.Client.MetricServer.Tests.csproj

@@ -7,7 +7,7 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
     <PackageReference Include="xunit.v3" Version="2.0.3" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="3.1.1">
+    <PackageReference Include="xunit.runner.visualstudio" Version="3.1.2">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
     </PackageReference>