Bump luyadev/yii-helpers from 1.2.0 to 1.2.1 in /core (#2148)

Bumps [luyadev/yii-helpers](https://github.com/luyadev/yii-helpers) from 1.2.0 to 1.2.1.
- [Release notes](https://github.com/luyadev/yii-helpers/releases)
- [Changelog](https://github.com/luyadev/yii-helpers/blob/master/CHANGELOG.md)
- [Commits](luyadev/yii-helpers@1.2.0...1.2.1)

---
updated-dependencies:
- dependency-name: luyadev/yii-helpers
  dependency-type: direct:production
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>