Pkg(3): develop package which depends on local/unregistered package

[ianfiske]

This doesn’t answer my exact question above, but following [ANN] Introducing Upgradathon Fridays - #3 by fredrikekre is working better for me. To start upgrading a [private] 0.6 package to 0.7 directly, I use develop on the remote git repo URL and then start working on the upgrade in my ~/.julia/dev/ directory.