Badge request: Sauce Labs

Hey,

Any plan to add [saucelabs](https://saucelabs.com)?

Thanks!

Start by reviewing how existing service badges are implemented in the Shields repository and how their tests define badge behavior. The request only identifies Sauce Labs, so determine the badge data and expected output before making changes; done means the service has a working badge covered by tests.

Written by the indexing model from the issue text.