Correct update message URL
Created by: nettrom
The update message lists a repo URL that results in an error when using it to upgrade:
Collecting git+https://github.com/neilpquinn/wmfdata/wmfdata.git@release
Cloning https://github.com/neilpquinn/wmfdata/wmfdata.git (to revision release) to /tmp/pip-req-build-8vc82m69
Running command git clone -q https://github.com/neilpquinn/wmfdata/wmfdata.git /tmp/pip-req-build-8vc82m69
remote: Not Found
fatal: repository 'https://nettrom@github.com/neilpquinn/wmfdata/wmfdata.git/' not found
This pull request updates update_message
so the URL it outputs matches the one in the README file, which works.