composer(deps): update rector/rector requirement || ^0.16.0

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@0.15.7...0.16.0)

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

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

composer.json

@@ -6,7 +6,7 @@
     "require": {
         "php": ">=7.4",
         "ergebnis/composer-normalize": "^2.28",
-        "rector/rector": "^0.15.7",
+        "rector/rector": "^0.15.7 || ^0.16.0",
         "sylius-labs/coding-standard": "^4.1.1",
         "vimeo/psalm": "^4.30 || ^5.0"
     },