Steps to Reproduce

1. Install flutter 3.3.10
2. Create a project that has some dependencies which are pinned to a version that is not the latest. For example, if package foo has version 1.0.1 as the latest version, lock on 1.0.0.

pubspec.yaml

dependencies:
  flutter:
    sdk: flutter
  foo: ^1.0.0

pubspec.lock

# Generated by pub
# See https://dart.dev/tools/pub/glossary#lockfile
packages:
  foo:
    dependency: "direct main"
    description:
      name: foo
      url: "https://pub.dartlang.org"
    source: hosted
    version: "1.0.0"

3. Run flutter pub get and notice that the package version is NOT upgraded since there is a lock file.
4. Upgrade to flutter 3.7.0
5. Run flutter pub get and notice that the package version IS upgraded because the lock file was totally regenerated and the old one was ignored.

Expected results:

pubspec.lock should always be honored.

Actual results:

pubspec.lock is ignored when upgrading to flutter 3.7.0