chore: bump minimum required PHP 8.2

[ddevsr]

Description
See #9667 (review)

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[samsonasik]

Rector php sets need to be updated to php82: true

CodeIgniter4/rector.php

Line 56 in 63e9ebd

->withPhpSets(php81: true)

[ddevsr]

@samsonasik Suggestion change in rector set PHP 8.2 can be split another PR?

[paulbalandan]

Can we also set up an issue tracking what PHP 8.2 features we can adopt? For one I can think of is the SensitiveParameter attribute.

[neznaika0]

See here:

CodeIgniter4/phpstan.neon.dist

Line 5 in 63e9ebd

phpVersion: 80100

and here:

CodeIgniter4/system/Debug/Exceptions.php

Line 90 in 63e9ebd

// @TODO remove this after dropping PHP 8.1 support.

Are we changing it?

[neznaika0]

Add to https://github.com/codeigniter4/CodeIgniter4/blob/4.7/user_guide_src/source/changelogs/v4.7.0.rst

**********
Highlights
**********

- Update minimal PHP requirement to 8.2.

If you wish, you can refresh the versions in the guide:
https://github.com/codeigniter4/CodeIgniter4/blob/4.7/user_guide_src/source/installation/installing_composer.rst
https://github.com/codeigniter4/CodeIgniter4/blob/4.7/user_guide_src/source/installation/upgrade_4xx.rst
https://github.com/codeigniter4/CodeIgniter4/blob/4.7/user_guide_src/source/intro/requirements.rst
and utils:
https://github.com/codeigniter4/CodeIgniter4/blob/develop/utils/composer.json

[neznaika0]

I'm not sure about the rule for readonly, but when a writeable property appears, you need to return readonly for the property. We can forget about it.
There are phpstan errors. Okay, we'll fix it later.

[michalsn]

If you're making these detailed updates, can you also edit warning secion in the README.md and update the line:

- The end of life date for PHP 8.1 will be December 31, 2025.

as well as add EOL for PHP 8.2? Thanks.

[ddevsr]

When version release 4.7 same as release PHP 8.5 GA, i'll make like this

- The end of life date for PHP 8.1 was December 31, 2025.
- The end of life date for PHP 8.2 will be December 31, 2026.

[michalsn]

Thank you @ddevsr