Create GitHub releases

#82 

This will create Github releases but without assets.

Assest can be enabled via https://github.com/forki/FSharp.ProjectScaffold/compare/fsprojects:master...forki:Github?expand=1#diff-2efaaa9f2632e3258cdcbc80f78883eaR220

/cc @shiftkey -> this will break you some new customers for Octokit ;-)