Use the new License API v2

[tdruez]

Current DejaCode API is deprecated.

[tdruez]

The code was updated to work with the API DejaCode v2 in the v2x_maintenance branch.

Since the username is not required anymore, here's the new usage:

genabout.py --extract_license --api_url='https://enterprise.dejacode.com/api/v2/licenses/' --api_key='<api_key>'

@chinyeungli please review changes and confirm everything is working fine. Next step is to remove the old API v1 from DejaCode.

[chinyeungli]

@tdruez Yes. This is working fine with your update