Bump the dev-dependencies group with 2 updates

Bumps the dev-dependencies group with 2 updates: [phpstan/extension-installer](https://github.com/phpstan/extension-installer) and [phpstan/phpstan](https://github.com/phpstan/phpstan).


Updates `phpstan/extension-installer` from 1.4.1 to 1.4.2
- [Release notes](https://github.com/phpstan/extension-installer/releases)
- [Commits](phpstan/extension-installer@1.4.1...1.4.2)

Updates `phpstan/phpstan` from 1.11.8 to 1.12.0
- [Release notes](https://github.com/phpstan/phpstan/releases)
- [Changelog](https://github.com/phpstan/phpstan/blob/1.12.x/CHANGELOG.md)
- [Commits](phpstan/phpstan@1.11.8...1.12.0)

---
updated-dependencies:
- dependency-name: phpstan/extension-installer
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: dev-dependencies
- dependency-name: phpstan/phpstan
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: dev-dependencies
...

Signed-off-by: dependabot[bot] <support@github.com>