Upgrade to PHP 8.x

• Added return types.
• Added isNumericKeys, isNulledValues and isMultiDimensional methods.
• Enhance get, has, set and delete methods.
• Changed helpers names.

1.0.3: Merge pull request #2 from oxidmod/bugfix/fix-internal-interfaces-met…

…hods-compatibility

bugfix: add missing ReturnTypeWillChange attributes

Support 8.1

1.0.2

support php 8.1

1.0.1

Update README.md

1.0.0

first commit