Upgrade to Go 1.21, PHP 8.2, Alpine 3.19

What does this MR do?

Upgrade to Go 1.21, PHP 8.2, Alpine 3.19.

NOTE: We don't have a go-fips:1.21, so we're forced to pull the latest minor release, that is registry.gitlab.com/gitlab-org/gitlab-runner/go-fips:1.21.5.

What are the relevant issue numbers?

None

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated for GitLab EE, if necessary
• Documentation created/updated for this project, if necessary
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Job definition updated, if necessary
  • Auto-DevOps template
  • Job definition example
  • CI Templates
• Conforms to the code review guidelines
• Conforms to the Go guidelines
• Security reports checked/validated by reviewer