build(deps-dev): update phpstan/phpstan requirement (#44)

Updates the requirements on [phpstan/phpstan](https://github.com/phpstan/phpstan) to permit the latest version.
- [Release notes](https://github.com/phpstan/phpstan/releases)
- [Commits](phpstan/phpstan@0.12.80...0.12.81)

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

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Author: dependabot-preview[bot]

composer.json

@@ -22,7 +22,7 @@
         "ergebnis/composer-normalize": "^2.13",
         "infection/infection": "^0.21.4",
         "phpstan/extension-installer": "^1.1",
-        "phpstan/phpstan": "^0.12.80",
+        "phpstan/phpstan": "^0.12.81",
         "phpstan/phpstan-phpunit": "^0.12.18",
         "phpunit/phpunit": "^9.5",
         "spatie/phpunit-snapshot-assertions": "^4.2",