composer(deps-dev): bump rector/rector in /tools/rector

Bumps [rector/rector](https://github.com/rectorphp/rector) from 0.18.13 to 1.0.3.
- [Release notes](https://github.com/rectorphp/rector/releases)
- [Commits](rectorphp/rector@0.18.13...1.0.3)

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

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

tools/rector/composer.json

@@ -1,5 +1,5 @@
 {
     "require-dev": {
-        "rector/rector": "^0.18.0"
+        "rector/rector": "^1.0.3"
     }
 }