Add dev and dependencies.svg targets to be build by gitlab and update go to 1.15

The vendor directory is a viral thing that forces everything needed to be there.

So that all the tools require by gitlab have been added there.

This is an unfortunate MR, as it's unfortunately doing way too much, too many different concerns.

I think it's valid still.

It also workarounds an issue with the current swag command, used by the dev build, which prevents it of working with vendor. This issue should is to be released on future versions of swag, which we are unable to use at the moment.