chore(example/deps): update dependency dart to >=3.12.1 <4.0.0

[renovate]

This PR contains the following updates:

Package	Update	Change
dart (source)	patch	>=3.12.0 <4.0.0 → >=3.12.1 <4.0.0

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Release Notes

dart-lang/sdk (dart)

v3.12.1

Compare Source

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Configuration

📅 Schedule: (in timezone Australia/Sydney)

• Branch creation
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• Automerge
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🚦 Automerge: Enabled.

♻ Rebasing: Whenever PR is behind base branch, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

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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: example/pubspec.lock

Command failed: flutter pub get --no-precompile
The current Dart SDK version is 3.12.0.

Because google_api_headers_example requires SDK version >=3.12.1 <4.0.0, version solving failed.


You can try the following suggestion to make the pubspec resolve:
* Try using the Flutter SDK version: 3.45.0-0.1.pre. 
Failed to update packages.