Bump FsUnit.xUnit from 5.4.0 to 5.6.0

Bumps [FsUnit.xUnit](https://github.com/fsprojects/FsUnit) from 5.4.0 to 5.6.0.
- [Release notes](https://github.com/fsprojects/FsUnit/releases)
- [Changelog](https://github.com/fsprojects/FsUnit/blob/master/RELEASE_NOTES.md)
- [Commits](fsprojects/FsUnit@5.4.0...5.6.0)

---
updated-dependencies:
- dependency-name: FsUnit.xUnit
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

src/FSharp.Control.TaskSeq.SmokeTests/FSharp.Control.TaskSeq.SmokeTests.fsproj

@@ -19,7 +19,7 @@
     <PackageReference Update="FSharp.Core" Version="7.0.401" />
     <PackageReference Include="FSharp.Control.TaskSeq" Version="0.4.0-alpha.1" />
     <PackageReference Include="FsToolkit.ErrorHandling.TaskResult" Version="4.10.0" />
-    <PackageReference Include="FsUnit.xUnit" Version="5.4.0" />
+    <PackageReference Include="FsUnit.xUnit" Version="5.6.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
     <PackageReference Include="xunit" Version="2.6.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.5.3">

src/FSharp.Control.TaskSeq.Test/FSharp.Control.TaskSeq.Test.fsproj

@@ -53,7 +53,7 @@
   <ItemGroup>
     <!-- align test project with minimal required version for TaskSeq, which is 6.0.1 at the moment -->
     <PackageReference Update="FSharp.Core" Version="6.0.1" />
-    <PackageReference Include="FsUnit.xUnit" Version="5.4.0" />
+    <PackageReference Include="FsUnit.xUnit" Version="5.6.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
     <PackageReference Include="xunit" Version="2.6.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.5.3">