Update dependency Selenium.WebDriver to v4.21.0

Author: renovate[bot]

examples/dotnet/SeleniumDocs/SeleniumDocs.csproj

@@ -11,7 +11,7 @@
       <PackageReference Include="MSTest.TestAdapter" Version="3.3.1" />
       <PackageReference Include="MSTest.TestFramework" Version="3.3.1" />
       <PackageReference Include="Selenium.Support" Version="4.20.0" />
-      <PackageReference Include="Selenium.WebDriver" Version="4.20.0" />
+      <PackageReference Include="Selenium.WebDriver" Version="4.21.0" />
     </ItemGroup>
 
     <ItemGroup>