Bump phpstan/phpstan from 1.11.4 to 1.11.6

Bumps [phpstan/phpstan](https://github.com/phpstan/phpstan) from 1.11.4 to 1.11.6.
- [Release notes](https://github.com/phpstan/phpstan/releases)
- [Changelog](https://github.com/phpstan/phpstan/blob/1.11.x/CHANGELOG.md)
- [Commits](phpstan/phpstan@1.11.4...1.11.6)

---
updated-dependencies:
- dependency-name: phpstan/phpstan
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>