Update the docs to include Sauce Labs options

Author: mdmintz

help_docs/customizing_test_runs.md

@@ -9,6 +9,7 @@ In addition to [settings.py](https://github.com/seleniumbase/SeleniumBase/blob/m
 * Change the automation speed (with Demo Mode)
 * Choose whether to run tests multi-threaded
 * Choose a BrowserStack server to run on
+* Choose a Sauce Labs server to run on
 * Choose a Selenium Grid to connect to
 * Choose a database to save results to
 * Choose a proxy server to connect to

help_docs/features_list.md

@@ -15,6 +15,7 @@
 * Can handle Google Authenticator logins by using the [Python one-time password library](https://pyotp.readthedocs.io/en/latest/).
 * Includes a hybrid-automation solution called **[MasterQA](https://github.com/seleniumbase/SeleniumBase/blob/master/seleniumbase/masterqa/ReadMe.md)** to speed up manual testing.
 * Includes integrations with [MySQL](https://github.com/seleniumbase/SeleniumBase/blob/master/seleniumbase/core/testcase_manager.py), [Selenium Grid](https://github.com/seleniumbase/SeleniumBase/tree/master/seleniumbase/utilities/selenium_grid), [Google Cloud](https://github.com/seleniumbase/SeleniumBase/tree/master/integrations/google_cloud/ReadMe.md), [Amazon S3](https://github.com/seleniumbase/SeleniumBase/blob/master/seleniumbase/plugins/s3_logging_plugin.py), and [NodeJS](https://github.com/seleniumbase/SeleniumBase/tree/master/integrations/node_js).
+* Has the ability to connect to a [BrowserStack](https://www.browserstack.com/automate#) or [Sauce Labs](https://saucelabs.com/products/web-testing/cross-browser-testing) Selenium Grid server.
 * Includes a [tool to convert Selenium IDE recordings](https://github.com/seleniumbase/SeleniumBase/tree/master/seleniumbase/utilities/selenium_ide) into clean, robust SeleniumBase scripts.
 * Written in Python, but can also make JavaScript calls using ``self.execute_script()``.
 * Includes useful Python decorators and password obfuscation methods. ([Learn more here](https://github.com/seleniumbase/SeleniumBase/blob/master/seleniumbase/common/ReadMe.md))