Update 00-First-Test.md

Switch order of Sauce.config elements.

Prior to this change, I got the following error.

unexpected response, code=404, content-type="text/plain"
  Unsupported OS/browser/version combo: OS: 'Firefox', Browser: 'windows', Version: '18.' (Selenium::WebDriver::Error::WebDriverError)
Merge pull request #2 from jeveleth/master

Update env setup docs