Given this package structure:

root
| -- packages
     | -- foo
     | -- bar

And bar is a peerDependency of foo.

When we publish a new version of foo and bar also update of the peerDependency in foo to the latest version.

We should only update the peer dependency on bar if the following conditions are met:

• When the peerDependency on bar was an exact version. So "bar": "^0.14 || ^15.0.0" should not be updated, but "bar": "0.5.6" should be updated. Question: what about "bar": "^0.5.6"?
• When the foo dependency is being published. i.e. we should not force a release of foo if bar is updated and we're running in independent versioning mode. Question: or should we force it?

Edit: Is this feature already implemented? https://github.com/lerna/lerna/blob/master/src/commands/PublishCommand.js#L452