[upd] pypi: Bump selenium from 4.20.0 to 4.21.0

Bumps [selenium](https://github.com/SeleniumHQ/Selenium) from 4.20.0 to 4.21.0.
- [Release notes](https://github.com/SeleniumHQ/Selenium/releases)
- [Commits](https://github.com/SeleniumHQ/Selenium/compare/selenium-4.20.0...selenium-4.21.0)

---
updated-dependencies:
- dependency-name: selenium
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

requirements-dev.txt

@@ -4,7 +4,7 @@ cov-core==1.15.0
 black==24.3.0
 pylint==3.1.0
 splinter==0.21.0
-selenium==4.20.0
+selenium==4.21.0
 Pallets-Sphinx-Themes==2.1.3
 Sphinx<=7.1.2; python_version == '3.8'
 Sphinx==7.3.7; python_version > '3.8'