Bump Verify.NUnit from 20.8.2 to 21.0.0

Bumps [Verify.NUnit](https://github.com/VerifyTests/Verify) from 20.8.2 to 21.0.0.
- [Release notes](https://github.com/VerifyTests/Verify/releases)
- [Commits](VerifyTests/Verify@20.8.2...21.0.0)

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

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

src/Orc.Theming.Tests/Orc.Theming.Tests.csproj

@@ -26,7 +26,7 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
     <PackageReference Include="PublicApiGenerator" Version="11.0.0" PrivateAssets="all" />
-    <PackageReference Include="Verify.NUnit" Version="20.8.2" />
+    <PackageReference Include="Verify.NUnit" Version="21.0.0" />
   </ItemGroup>
 
   <ItemGroup>