7.0.0: Amazon Linux 2023

This major release migrates to Amazon Linux 2023. Amazon Linux 2 end of support date (End of Life, or EOL) will be on 2026-06-30 as announced at https://aws.amazon.com/amazon-linux-2/faqs/

• Merged PR #28: Migrate from AL2 to AL2023 - @thekid
• Added PHP 8.6 to the test matrix - @thekid