Fix phpstan, downgrade to 2.1.12

Related: larastan/larastan#1355

Author: yajra

composer.json

@@ -22,7 +22,7 @@
   },
   "require-dev": {
     "maatwebsite/excel": "^3.1.40",
-    "nunomaduro/larastan": "^2.1",
+    "nunomaduro/larastan": "2.1.*",
     "orchestra/testbench": "^7.3",
     "rap2hpoutre/fast-excel": "^3.2",
     "barryvdh/laravel-snappy": "^1.0"