build(deps): bump Verify.Xunit from 19.14.0 to 20.3.0 in /src

Bumps [Verify.Xunit](https://github.com/VerifyTests/Verify) from 19.14.0 to 20.3.0.
- [Release notes](https://github.com/VerifyTests/Verify/releases)
- [Commits](VerifyTests/Verify@19.14.0...20.3.0)

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

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

src/Directory.build.props

@@ -53,7 +53,7 @@
     <PackageReference Include="FluentAssertions" Version="6.11.0" />
     <PackageReference Include="Microsoft.Reactive.Testing" Version="5.0.0" />
     <PackageReference Include="PublicApiGenerator" Version="11.0.0" />
-    <PackageReference Include="Verify.Xunit" Version="19.14.0" />
+    <PackageReference Include="Verify.Xunit" Version="20.3.0" />
   </ItemGroup>
 
   <ItemGroup Condition="$(IsTestProject)">