Update composer.json, remove unused abandoned dep

composer.json

@@ -30,7 +30,6 @@
         "predis/predis": "^1.1",
         "spatie/laravel-backup": "^5.0.0",
         "spatie/laravel-image-optimizer": "^1.1",
-        "spatie/laravel-partialcache": "^1.3",
         "stevebauman/purify": "2.0.*"
     },
     "require-dev": {