PHP 8.2 will only receive security patches starting at the end of
November[1], so it makes sense to bump the default version forward.
I looked through all modules with the substring `pkgs.php`[2] and all of
the usages looked fine or were fixed in a commit before this one.
[1] https://www.php.net/supported-versions.php
[2] I didn't take `with`/`let ... in` things into account, but honestly,
if an application doesn't work with a newer PHP, it should probably
be pinned down instead of blindly relying on `pkgs.php`.
d2ed89833b