Update rector/rector requirement from 0.15.1 to 0.15.12

Updates the requirements on [rector/rector](https://github.com/rectorphp/rector) to permit the latest version.
- [Release notes](https://github.com/rectorphp/rector/releases)
- [Commits](rectorphp/rector@0.15.1...0.15.12)

---
updated-dependencies:
- dependency-name: rector/rector
  dependency-type: direct:development
...

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

composer.json

@@ -23,7 +23,7 @@
         "phpstan/phpstan-phpunit": "^1.3",
         "phpstan/phpstan-strict-rules": "^1.4",
         "phpunit/phpunit": "^9.5",
-        "rector/rector": "0.15.1",
+        "rector/rector": "0.15.12",
         "spatie/phpunit-watcher": "^1.23",
         "symplify/easy-coding-standard": "^11.2.7",
         "vimeo/psalm": "^5.6"