feat(cli): detect bun.lock file for the "upgrade" cmd

[Dustin-Z]

What kind of change does this PR introduce?

• Bugfix
• Feature
• Documentation
• Code style update
• Refactor
• Build-related changes
• Other, please describe:

Does this PR introduce a breaking change?

• Yes
• No

The PR fulfills these requirements:

• It's submitted to the dev branch (or v[X] branch)
• When resolving a specific issue, it's referenced in the PR's title (e.g. fix: #xxx[,#xxx], where "xxx" is the issue number)
• It's been tested on a Cordova (iOS, Android) app
• It's been tested on an Electron app
• Any necessary documentation has been added or updated in the docs or explained in the PR's description.

If adding a new feature, the PR's description includes:

• A convincing reason for adding this feature (to avoid wasting your time, it's best to start a new feature discussion first and wait for approval before working on it)

Other information:

In version 1.1.39 of Bun they have introduced a text-based lockfile format (bun.lock) as an alternative to the binary lockfile (bun.lockb). It will be the default soon.
For more info see Bun's blog post.

This change will make quasar upgrade -i command detect Bun as a package manager if the new lockfile format is used.

I don't know how to test it. Can you help with with that?
I tried running my modified version in a Quasar project with pending updates using

bun ~/git/my-quasar-fork/cli/bin/quasar.js upgrade -i

But without success. It doesn't even detect my pending update. Running the original command quasar upgrade (without -i) shows that there is an update. So I don't think that's the right way to test it.