build: bump phpstan/phpstan from 1.11.7 to 1.12.4 (#83)

Bumps [phpstan/phpstan](https://github.com/phpstan/phpstan) from 1.11.7 to 1.12.4.
- [Release notes](https://github.com/phpstan/phpstan/releases)
- [Changelog](https://github.com/phpstan/phpstan/blob/2.0.x/CHANGELOG.md)
- [Commits](phpstan/phpstan@1.11.7...1.12.4)

---
updated-dependencies:
- dependency-name: phpstan/phpstan
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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