Fix Scalar Unions

• Fixed a regression from the v4.1.5 scalar union patch merged from upstream Dice.

Scalar Union Support

Constructor params that have a union type are supported, however only for scalar types at this stage.

Fixes from upstream

Fixes the following:

• Support nullable class type hints
• Stop some parameters getting counted twice - Level-2#195
• Fix issue where 'shareInstances' resolve but fail to propagate - Level-2#201

Support for Psalm static type checking on create() method

v4.1.3

Added psalm typehints to create function

Fixes named shared built-in instances

Found and fixed a regression for for named shared build-in instances, now covered by unti tests.

Fix constructor parameter order

This update fixes constructor parameter ordering: Level-2#181

PHP 8 Support

Dice now offers basic PHP8 support, however it does not currently resolve union types.