Merge pull request #80 from codeigniter4/dependabot/composer/rector/rector-0.15.21

chore(deps-dev): update rector/rector requirement from 0.15.19 to 0.15.21

Author: samsonasik

composer.json

@@ -39,7 +39,7 @@
     "require-dev": {
         "codeigniter4/framework": "^4.1",
         "icanhazstring/composer-unused": "^0.8.2",
-        "rector/rector": "0.15.19"
+        "rector/rector": "0.15.21"
     },
     "minimum-stability": "dev",
     "prefer-stable": true,