Request: Support for non-Git VCS repos

[paulsnar]

Right now, the only two options of how to distribute a jpm package is either via a Git repo or via a tarball. Though the latter is flexible enough to accommodate pretty much all use cases not covered by Git alone, it would still be nice if dependencies could refer to other VCSes as well – notably, Mercurial and Fossil.

For context, Go, which also has some infra to support VCSes in its build tooling, supports Git, Hg, Fossil, but also Bazaar and Subversion. That said, given the overwhelming dominance of Git over other VCSes in practice, I'm not sure whether this is worthwhile, so this can also be declared out of scope.

[sogaiu]

For some related past discussion that touches on this a bit: https://github.com/janet-lang/janet/issues/631