build(deps): bump the selenium-dependencies group (#783)

Bumps the selenium-dependencies group in /src/Appium.Net with 2 updates: [Selenium.Support](https://github.com/SeleniumHQ/selenium) and [Selenium.WebDriver](https://github.com/SeleniumHQ/selenium).


Updates `Selenium.Support` from 4.20.0 to 4.21.0
- [Release notes](https://github.com/SeleniumHQ/selenium/releases)
- [Commits](SeleniumHQ/selenium@selenium-4.20.0...selenium-4.21.0)

Updates `Selenium.WebDriver` from 4.20.0 to 4.21.0
- [Release notes](https://github.com/SeleniumHQ/selenium/releases)
- [Commits](SeleniumHQ/selenium@selenium-4.20.0...selenium-4.21.0)

---
updated-dependencies:
- dependency-name: Selenium.Support
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: selenium-dependencies
- dependency-name: Selenium.WebDriver
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: selenium-dependencies
...

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

Author: dependabot[bot]

src/Appium.Net/Appium.Net.csproj

@@ -58,8 +58,8 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="Selenium.Support" Version="4.20.0" />
-    <PackageReference Include="Selenium.WebDriver" Version="4.20.0" />
+    <PackageReference Include="Selenium.Support" Version="4.21.0" />
+    <PackageReference Include="Selenium.WebDriver" Version="4.21.0" />
     <PackageReference Include="System.Drawing.Common" Version="8.0.5" />
   </ItemGroup>
   <ItemGroup>