chore: use personal access token (knqyf263#186)

Close knqyf263#107 by properly handle last newline (knqyf263#108)

It seems that TrimSpace was intended to remove the last newline.
However, using strings.TrimSpace also removes other whitespace
charactes which causes the selected snippet not be able to be
presented on screen.

Update Travis CI to Go 1.12.0

Use go module

Adds the option to define sync access tokens via environment variables (

knqyf263#89)

The url parameter is added to be able to choose the url to be used as…

… a GitLab repository (knqyf263#77)