Bump xunit.runner.visualstudio from 2.8.2 to 3.1.5

---
updated-dependencies:
- dependency-name: xunit.runner.visualstudio
  dependency-version: 3.1.5
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

api/tests/ProposalSystem.Tests/ProposalSystem.Tests.csproj

@@ -12,7 +12,7 @@
     <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="8.0.28" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
     <PackageReference Include="xunit" Version="2.9.3" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2">
+    <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>