Add support to PHP 8.3

[llaville]

• [x] create branch 7.1
• [ ] new sniffs to detect PHP 8.3 features
  • [ ] PHP Core - Readonly Amendments
  • [x] PHP Core - Typed Class Constants
  • [ ] PHP Core - Closures created from magic methods
  • [x] PHP Core - Override Attribute
  • [x] PHP Core - Static variable initializers
  • [x] PHP Core - Fetch class constant dynamically syntax

[llaville]

Included in release 7 1.0