chore(deps): Bump VerifyVersion from 28.4.0 to 28.6.0

Bumps `VerifyVersion` from 28.4.0 to 28.6.0.

Updates `Verify.Xunit` from 28.4.0 to 28.6.0
- [Release notes](https://github.com/VerifyTests/Verify/releases)
- [Commits](VerifyTests/Verify@28.4.0...28.6.0)

Updates `Microsoft.NETFramework.ReferenceAssemblies` from 1.0.3 to 1.0.3
- [Commits](https://github.com/Microsoft/dotnet/commits)

---
updated-dependencies:
- dependency-name: Verify.Xunit
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: Microsoft.NETFramework.ReferenceAssemblies
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

test/TestHelpers/TestHelpers.csproj

@@ -7,7 +7,7 @@
   </PropertyGroup>
 
   <PropertyGroup>
-    <VerifyVersion>28.4.0</VerifyVersion>
+    <VerifyVersion>28.6.0</VerifyVersion>
     <VerifyVersion Condition="'$(TargetFramework)'=='net5.0' Or '$(TargetFramework)'=='netstandard2.0' Or '$(TargetFramework)'=='net462'">20.8.2</VerifyVersion>
     <VerifyPublicApi Condition="'$(VerifyPublicApi)'==''">true</VerifyPublicApi>
     <DefineConstants Condition="'$(VerifyPublicApi)'=='true'">$(DefineConstants);VERIFY_PUBLIC_API</DefineConstants>