Update filename from 'MicrosoftWebDriver.exe' to 'msedgedriver'

[aruiz-futurefinance]

• It looks in the time since this service was created, MS has changed the name of the driver from MicrosoftWebDriver.exe to msedgedriver.exe

  • https://developer.microsoft.com/en-us/microsoft-edge/tools/webdriver/

• Is it also possible to add a check for the OS used

command = process.platform === 'win32' ? 'msedgedriver.exe' : 'msedgedriver';

• This will help if/when Add edgedriver to PATH automatically sitespeedio/edgedriver#1 is also resolved

I can raise a PR if it helps

[RafalSkorka]

Please check if it works now for you, then I'll release a new npm package.