Adds stack sig sign sdist and stack upload --sign

[dysinger]

No description provided.

[snoyberg]

I think this can be replaced by some functions in Stack.Package, which will (1) avoid code duplication, and (2) ensure that Cabal library workarounds (like BOM stripping) are centralized to one place.

[borsboom]

@dysinger / @snoyberg: I see there have been some more commits since the last comments. Is this ready to merge?

[snoyberg]

I still see that some of my comments seem to be unaddressed.

[dysinger]

I think the only one I haven't address is switching to System.Process.Read. This would be hard for one of the functions (verify) which needs to stream in on stdin and consume stderr after (& see a successful exit code). @borsboom talked about maybe adding to System.Process.Read in the future. I think this branch is ready to merge (after CI).

[borsboom]

Can you add an entry to the change log, and also add/update any relevant documentation in doc/? If you'd rather I just merge this now and you'll come back to do those later, that's ok too, just let me know.

[dysinger]

added a few lines to the ChangeLog.md & also to the GUIDE.md

[borsboom]

Cool. Might be worth moving this to the "major changes" section of the changelog; I think it's worth calling extra attention to it.