Bump php-webdriver/webdriver from 1.8.0 to 1.8.1

Bumps [php-webdriver/webdriver](https://github.com/php-webdriver/php-webdriver) from 1.8.0 to 1.8.1.
- [Release notes](https://github.com/php-webdriver/php-webdriver/releases)
- [Changelog](https://github.com/php-webdriver/php-webdriver/blob/master/CHANGELOG.md)
- [Commits](https://github.com/php-webdriver/php-webdriver/compare/1.8.0...1.8.1

)

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