bufio's reader.ReadString includes any CRLF characters and we don't
want these in the resulting token because this leads to errors in the
authentication like this:

```
✗ failed to get Git repository
"https://github.com/kingdon-ci/jenkins-infra": Get
"https://api.github.com/repos/kingdon-ci/jenkins-infra

": net/http:
invalid header field value "Bearer gho_NNNNNsecrettokenMMMMM\n" for
key Authorization
```

Signed-off-by: Max Jonas Werner <mail@makk.es>