quick hack to fix update check service

[Dirk Hohndel]

I think I have something that works - but it could really benefit from some testing.

Would people mind running old and new versions of Subsurface (on Linux, macOS, and Windows) and check for an update (that's under the Help menu entry)?
Does the response make sense? If not, what does it say, what should it say.

In order to get a feel for how much this has tested, would you also send "success" emails (including what combinations you tested)?

Thanks

/D