Summary

We are upgrading to php 8.1 (PLANET-7350) which is EOL at the end of this year. We can add php 8.3 tests pipeline already to see if we have any deprecation issues we need to fix.

Requirements

• Add php8.3 images in planet4-circleci-unit-tests. Remove 7.4. (done)
• Add a php-8.3 tests job to run along side with php-8.1 in our two app repos.
  • When removing php7.4, drop `"doctrine/instantiator": "^1.5.0"` declaration from master-theme/gutenberg-block composer.json file
• If we have many deprecation warnings try also running php8.2 since we may need to upgrade to this version first.
• Add follow up tickets if certain fixes are required to be php8.3 compatible.