Release v0.12.1

[Timeless0911]

No description provided.

[Copilot]

Pull Request Overview

This PR releases version 0.12.1 by bumping the version numbers across all package.json files in the monorepo.

• Updates version from 0.12.0 to 0.12.1 across all packages
• Maintains consistency across the monorepo packages
• Follows standard semantic versioning for a patch release

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
packages/plugin-dts/package.json	Version bump to 0.12.1 for the DTS plugin package
packages/create-rslib/package.json	Version bump to 0.12.1 for the create-rslib package
packages/core/package.json	Version bump to 0.12.1 for the core package

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