yarn install --flat does not work in workspace testing

[FredKSchott]

There are a few issues uncovered with running yarn install --flat in a workspace:

1. Yarn has a bug where the git hash of a locally referenced dependency (that's also been converted) is read as the package "version", causing errors inside of yarn ("83c19296e1cc615c224df685c497a8e5e38dcdf5 is not a valid version") .
2. The new, desired post-conversion version is written to each package.json, which can cause conflicts when installing (ex: `can't flatten semver ranges "3.0.0-pre.1" & "3.0.0-pre.2").

Reverting to use npm install now, but we should fix this so that we have proper support for yarn.

[stramel]

Maybe this isn't the place to discuss this, but I'm curious if you guys are planning on moving forward with yarn or npm's asset module whenever it is finished?

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.