composer(deps-dev): update rector/rector requirement

Updates the requirements on [rector/rector](https://github.com/rectorphp/rector) to permit the latest version.

Updates `rector/rector` to 1.2.6
- [Release notes](https://github.com/rectorphp/rector/releases)
- [Commits](rectorphp/rector@1.2.5...1.2.6)

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

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

composer.json

@@ -38,7 +38,7 @@
     "phpstan/phpstan-deprecation-rules": "^1.2.1",
     "phpstan/phpstan-phpunit": "^1.4.0",
     "phpunit/phpunit": "^10.5.26",
-    "rector/rector": "^1.2.5",
+    "rector/rector": "^1.2.6",
     "rector/type-perfect": "^1.0.0",
     "symplify/phpstan-rules": "^13.0.1",
     "tomasvotruba/cognitive-complexity": "^0.2.3",