Add documentation about store parameter on cache tag

For statamic/cms#10318

content/collections/tags/cache.md

@@ -20,6 +20,10 @@ parameters:
     name: scope
     type: 'string'
     description: 'Sets the [cache scope](#scope). Three possible values: `site`, `page` or `user`. Has no effect when using the `key` parameter.'
+  -
+    name: store
+    type: 'string'
+    description: 'Sets the [cache store](https://laravel.com/docs/cache#accessing-multiple-cache-stores) the cache tag uses to store and retrieve the cached values.'
 stage: 4
 id: 1d0d2d1f-734b-4360-af7a-6792bf670bc7
 ---