Add yarn berry dependency upgrade example for Next 12 to 13 upgrade documentation.

[matthew-heath]

This PR adds an example yarn up command to bump the relevant dependencies when using yarn berry for the Next 12 to Next 13 upgrade. One thing to possibly note is that yarn up is not scoped to a single workspace like yarn upgrade in classic - to get around this when in multiple workspaces, the -i/--interactive flag can be passed.

Update - can upgrade dependencies in both yarn classic/berry using yarn add ...@latest, this may be more straight forward than having two separate commands.

Documentation / Examples

• Make sure the linting passes by running pnpm build && pnpm lint
• The "examples guidelines" are followed from our contributing doc

[balazsorban44]

Looks like this is compatible with yarn@1, so it should fine.