composer(deps-dev): bump phpstan/phpstan from 0.12.88 to 0.12.89

Bumps [phpstan/phpstan](https://github.com/phpstan/phpstan) from 0.12.88 to 0.12.89.
- [Release notes](https://github.com/phpstan/phpstan/releases)
- [Commits](phpstan/phpstan@0.12.88...0.12.89)

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

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

composer.json

@@ -31,7 +31,7 @@
     "ergebnis/phpstan-rules": "~0.15.3",
     "ergebnis/test-util": "^1.5.0",
     "phpstan/extension-installer": "^1.1.0",
-    "phpstan/phpstan": "~0.12.84",
+    "phpstan/phpstan": "~0.12.89",
     "phpstan/phpstan-deprecation-rules": "~0.12.6",
     "phpstan/phpstan-phpunit": "~0.12.19",
     "phpstan/phpstan-strict-rules": "~0.12.9",