release please with root + workspaces

[lukekarrys]

This is not currently an issue since we currently only use workspaces in the cli and we DONT use release please to release the cli.

But I wanted to point out that currently release-please cannot exclude any paths when creating a release (googleapis/release-please#908). So if we were to publish the cli in the future, we would need to move it into its own workspace inside a private: true root workspace.

This is something to keep in mind if we plan to do that and if we plan to make other repos into monorepos.

[lukekarrys]

This was done by #174