PathNotFoundException: Cannot open file - pubspec.lock

When using Pub workspaces for monorepos, pubspec.lock is not generated in packages.

So, the following handling is needed.

```dart
final pubspecLockFile = File('$currentPath/pubspec.lock');
if (pubspecLockFile.existsSync()) {
final pubspecLock = loadYaml(pubspecLockFile.readAsStringSync());
dependencies.addAll(pubspecLock['packages'].keys);
}
```

Search the repository for the code that reads pubspec.lock and builds the dependency list, then compare it with the handling shown in issue #85. Verify the behavior for a Pub workspace package without pubspec.lock, and consider a regression test if the existing test structure covers this path.

Written by the indexing model from the issue text.