Issue Type: Bug

1. Click sign in to github in the status bar
2. Follow the steps to authenticate
3. Let uri handler in vs code open authentication uri

🐛 => stuck signing in. the extension does not handle the uri and store the token

Extension version: 0.333.1
VS Code version: Code - Insiders 1.30.0-insider (cd5b4d1bb3fc7e509fba077095b2b280b8ff7161, 2018-11-29T06:32:54.872Z)
OS version: Windows_NT x64 10.0.17763