is `-~~` really needed in dependency constraints?

this came up on IRC, so I figured I'd file it here as well so we don't forget about it. not urgent in any fashion

is the -~~ debcargo adds to generated versioned dependencies actually needed? git history tells me that it used to be just ~~, but that broke for prerelease versions of crates since they have a ~ in the upstream version. but since we don't handle debian revisions at all in debcargo (when reasoning about versioned dependencies), shouldn't just having the upstream version as bound be enough?