Bump xunit.runner.visualstudio from 2.5.5 to 2.5.7 (#554)

Bumps [xunit.runner.visualstudio](https://github.com/xunit/visualstudio.xunit) from 2.5.5 to 2.5.7.
- [Release notes](https://github.com/xunit/visualstudio.xunit/releases)
- [Commits](xunit/visualstudio.xunit@2.5.5...2.5.7)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

tests/ImageSort.UnitTests/ImageSort.UnitTests.csproj

@@ -18,7 +18,7 @@
     <PackageReference Include="ReactiveUI" Version="19.5.41" />
     <PackageReference Include="ReactiveUI.Testing" Version="19.5.41" />
     <PackageReference Include="xunit" Version="2.6.3" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.5">
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.7">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>