build(deps): bump Verify.Xunit from 17.10.2 to 18.2.1 in /src (#3408)

Bumps [Verify.Xunit](https://github.com/VerifyTests/Verify) from 17.10.2 to 18.2.1.
- [Release notes](https://github.com/VerifyTests/Verify/releases)
- [Commits](VerifyTests/Verify@17.10.2...18.2.1)

---
updated-dependencies:
- dependency-name: Verify.Xunit
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

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

Author: dependabot[bot]

src/Directory.build.props

@@ -52,7 +52,7 @@
     <PackageReference Include="Microsoft.Reactive.Testing" Version="5.0.0" />
     <PackageReference Include="PublicApiGenerator" Version="10.3.0" />
     <PackageReference Include="coverlet.msbuild" Version="3.1.2" PrivateAssets="All" />
-    <PackageReference Include="Verify.Xunit" Version="17.10.2" />
+    <PackageReference Include="Verify.Xunit" Version="18.2.1" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(IsTestProject)' != 'true'">