Add support to new PHP 8.3 still under development

[llaville]

New Feature request

Summary

Add support to new PHP version still under development.

Todo

• create new branch 6.0
• add all new features of PHP 8.3 : read more at https://php.watch/versions/8.3 and https://stitcher.io/blog/new-in-php-83

Checkpoints

• RC3 is now fully supported with branch 6.0 (commit 3ed6e5c)
• RC4 is now fully supported with branch 6.0 (commit 8603fa7)
• RC5 is now fully supported with branch 6.0 (commit 1f040df)
• RC6 is now fully supported with branch 6.0 (commits 6f88bb2, 15b3039 and 6bae879)