Bump phpstan/phpstan from 1.8.0 to 1.8.1 (#160)

Bumps [phpstan/phpstan](https://github.com/phpstan/phpstan) from 1.8.0 to 1.8.1.
- [Release notes](https://github.com/phpstan/phpstan/releases)
- [Changelog](https://github.com/phpstan/phpstan/blob/1.8.x/CHANGELOG.md)
- [Commits](phpstan/phpstan@1.8.0...1.8.1)

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

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

composer.json

@@ -10,7 +10,7 @@
 		"phpgt/session": "1.*"
 	},
 	"require-dev": {
-		"phpstan/phpstan": "v1.8.0",
+		"phpstan/phpstan": "v1.8.1",
 		"phpunit/phpunit": "v9.5.21"
 	},