Update to lerna 6

[jtpio]

Update to the latest lerna version: https://github.com/lerna/lerna/releases/tag/v6.0.0

This new major version includes some task pipeline configuration by default now (via nx), which could be leveraged in this repo to speed up the build and enhance the developer experience: https://lerna.js.org/docs/concepts/task-pipeline-configuration

[github-actions]

👈 Launch a Binder on branch jtpio/notebook/update-lerna

[jtpio]

Looks like some changes to the releaser actions lead to GITHUB_OUTPUT being create on disk:

$ node ./buildutils/lib/release-bump.js --force --skip-commit next
> git status
On branch main
Untracked files:
  (use "git add <file>..." to include in what will be committed)
	GITHUB_OUTPUT

[jtpio]

This seems required for now as it seems to be breaking the releaser check-npm step currently.

Will track that in a different issue.