Problems with github scopes

[lexoyo]

Hello
Just to keep track of this, in my previous fix to be able to change github scopes (#154) there are these things I am not sure about

1- in this line, I am not sure GH API uses the X-OAuth-Scopes but if it does we probably want to change it to this.permission? for now it works for me so we should probably remove it
2- the connector expects the scope to be in the form scope=xxx, yyy, ... where intuitively I would expect just xxx, yyy, ...