docs(migration): Adding a section for upgrading packages

[tsteuwer]

Adding a note that NestJS doesn't include an update command and to use npm-check-updates per Member recommendation.

The reason why I'd like to add this is I was recently looking to upgrading from V9 to V10 and figured the CLI included an update command but it was removed. Looking into this more it was recommended by @kamilmysliwiec to use npm-check-updates. I figured others would benefit from this like I did by adding it to the Migration guide.

If no one thinks this is useful like I did, we can close this.

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/nestjs/docs.nestjs.com/blob/master/CONTRIBUTING.md

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Docs
• Other... Please describe:

What is the current behavior?

There is no current update command and it's recommended to use ncu.

What is the new behavior?

A note that Nest CLI does not include an update command (yet) and to manually upgrade packages or use ncu.

Does this PR introduce a breaking change?

• Yes
• No

Other information

N/A

[Tony133]

Actually the "update" command was included in the CLI of Nest up to version 8 of NestJS but it was removed because it didn't update dependencies correctly and had stability problems, see screenshot

if we really want to add a warning or a notice, I would say add it in the CLI section: https://docs.nestjs.com/cli/overview

[tsteuwer]

That's fine with me as long as everyone's in agreement with that @Tony133 . Who do we need to confirm with on if it should be in migration or over on the CLI page?

[kamilmysliwiec]

LGTM