Bump rector/rector from 1.0.4 to 2.1.0

Bumps [rector/rector](https://github.com/rectorphp/rector) from 1.0.4 to 2.1.0.
- [Release notes](https://github.com/rectorphp/rector/releases)
- [Commits](rectorphp/rector@1.0.4...2.1.0)

---
updated-dependencies:
- dependency-name: rector/rector
  dependency-version: 2.1.0
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

composer.json

@@ -4,7 +4,7 @@
         "phan/phan": "^5.0",
         "friendsofphp/php-cs-fixer": "^3.5",
         "php-parallel-lint/php-parallel-lint": "^1.3",
-        "rector/rector": "^1.0"
+        "rector/rector": "^2.1"
     },
     "require": {
         "robmorgan/phinx": "^0.12",