`updater.py` is no longer parsing ChromeDriver version numbers correctly

[atenni]

It seems that around the start of March 2019 Google have changed their version numbering scheme (see ChromeDriver download page), and this is causing Travis to not update the package on PyPi.

Two problems that I can see are:

1. Google are currently using four digits (70.x.xxxx.xx) instead of two (2.xx). This is a problem in updater.py here and here.
2. Google are now using version numbers greater than 70 to keep inline with Chrome Browser. This is a problem in updater.py here.

I'm not sure that the checks linked to above are relevant anymore, and removing them allowed updater.check_for_update to return the correct highest_version for me – currently 76.0.3809.25

Let me know if my assumptions are correct and I'll be happy to send a pull request.