PHP 8.1 minimum version prep

README.md

@@ -158,12 +158,12 @@ the following requirements:
 
 * Your custom collection class must implement **\VersatileCollections\StrictlyTypedCollectionInterface** which currently contains the methods below:
 
-    * **public function checkType($item): bool** : it must return true if `$item` is of the expected type or false otherwise
+    * **public function checkType(mixed $item): bool** : it must return true if `$item` is of the expected type or false otherwise
     * **public function getTypes()** : it must return an instance of **\VersatileCollections\StringsCollection** of strings representing the name(s) of the expected type(s)
 
 * Your custom collection class should use **\VersatileCollections\StrictlyTypedCollectionInterfaceImplementationTrait** (which contains implementation of the methods in **\VersatileCollections\StrictlyTypedCollectionInterface**). If you choose not to use **\VersatileCollections\StrictlyTypedCollectionInterfaceImplementationTrait**, then you will have to implement all the methods specified in **\VersatileCollections\StrictlyTypedCollectionInterface** and make sure you call the **checkType($item)** method in every method where you add items to or modify items in the collection such as **offsetSet($key, $val)**  and throw an **VersatileCollections\Exceptions\InvalidItemException** exception whenever **checkType($item)** returns false. If you use **\VersatileCollections\StrictlyTypedCollectionInterfaceImplementationTrait** in your custom collection class but add new methods that also add items to or modify items in the collection you can use the helper method **isRightTypeOrThrowInvalidTypeException($item, $calling_functions_name)** provided in **\VersatileCollections\StrictlyTypedCollectionInterfaceImplementationTrait** to validate items (it will automatically throw an exception for you if the item you are validating is of the wrong type; see **\VersatileCollections\StrictlyTypedCollectionInterfaceImplementationTrait::offsetSet($key, $val)** for an example of how this helper method should be used).
 
-* You can optionally override **StrictlyTypedCollectionInterfaceImplementationTrait::__construct(...$arr_objs)** with a constructor
+* You can optionally override **StrictlyTypedCollectionInterfaceImplementationTrait::__construct(mixed ...$arr_objs)** with a constructor
 with the same signature but with the specific type. For example, **__construct(\PDO ...$pdo_objs)** ensures that only instances of
 **\PDO** can be injected into the constructor via argument unpacking. 
 
@@ -188,7 +188,7 @@ class PdoCollection implements StrictlyTypedCollectionInterface { //1. Implement
      * @return bool true if $item is of the expected type, else false
      * 
      */
-    public function checkType($item): bool { //4. implement interface methods not implemented in trait above
+    public function checkType(mixed $item): bool { //4. implement interface methods not implemented in trait above
 
         return ($item instanceof \PDO);
     }