Update dependencies in package manager after framework update

[schlessera]

After a version change of the WP-CLI framework, we should run a composer update inside of the package manager's folder to update the dependencies that were installed for external commands.

Right now, an update for the WP-CLI framework can require versions of libraries that don't match the ones installed with the package manager. As the package manager commands are meant to be able to override those that are bundled, this means that the outdated libraries take precedence.

This causes errors like in wp-cli/doctor-command#113 and #4330 .

[danielbachhuber]

After a version change of the WP-CLI framework, we should run a composer update inside of the package manager's folder to update the dependencies that were installed for external commands.

Realistically, I think we can only do this at the end of the wp cli update process, not when someone is updating via wget.

Also, it'd be better to call wp package update over requiring the composer binary to be on the system.

[danielbachhuber]

On second thought, calling wp package update is non-trivial and could cause other problems:

1. wp package update fails because of memory issues.
2. wp package update fails because of dependency conflict.

Because this is a minority use case, I think we should instead solve this with documentation and log output.

[gitlost]

It would be good to have a reproducible instance of this bug, as as mentioned in slack, neither wp-cli/doctor-command#113 (stale composer.json) nor #4330 (packages not installed??) seem to apply.