Update dependency dart_either to v2

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
dart_either (source)	dependencies	major	^1.0.0 -> 2.0.0

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Release Notes

hoc081098/dart_either (dart_either)

v2.0.0

Compare Source

• Require Dart 3.0.0 or higher >=3.0.0 <4.0.0.

• Make Either a sealed class, EitherEffect a sealed class, and ControlError a final class.
  Now you can use exhaustive switch expressions on Either instances.

  final Either<String, int> either = Either.right(10);
  
  // Use the `when` method to handle
  either.when(
    ifLeft: (l) => print('Left: $l'),
    ifRight: (r) => print('Right: $r'),
  ); // Prints Right: Either.Right(10)
  
  // Or use Dart 3.0 switch expression syntax 🤘
  print(
    switch (either) {
      Left() => 'Left: $either',
      Right() => 'Right: $either',
    },
  ); // Prints Right: Either.Right(10)

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Configuration

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[renovate]

⚠️ Artifact update problem

Renovate failed to update an artifact related to this branch. You probably do not want to merge this PR as-is.

♻ Renovate will retry this branch, including artifacts, only when one of the following happens:

• any of the package files in this branch needs updating, or
• the branch becomes conflicted, or
• you click the rebase/retry checkbox if found above, or
• you rename this PR's title to start with "rebase!" to trigger it manually

The artifact failure details are included below:

File name: pubspec.lock

Command failed: flutter pub upgrade dart_either
Because rxdart_ext 0.2.9 depends on dart_either ^1.0.0 and no versions of rxdart_ext match >0.2.9 <0.3.0, rxdart_ext ^0.2.9 requires dart_either ^1.0.0.
So, because batch_api_demo depends on both rxdart_ext ^0.2.9 and dart_either 2.0.0, version solving failed.


You can try one of the following suggestions to make the pubspec resolve:
* Consider downgrading your constraint on rxdart_ext: flutter pub add rxdart_ext:^0.2.5
* Consider downgrading your constraint on dart_either: flutter pub add dart_either:^1.0.0
Failed to update packages.