Add PHP 8.5 variants

[jnoordsij]

Modelled after #281.

PHP 8.5 is supported for 11.3+ (and is intended to be the minimum version for the upcoming 12.x major).
See also https://www.drupal.org/docs/getting-started/system-requirements/php-requirements.
Note that the default version for existing images will remain 8.4.

This PR also takes the opinionated choice of dropping 8.4 on 10.6/11.3, given upstream recommends using PHP 8.4 for these, to reduce the number of builds. Alternatively, this may be done for 11.3 only (to effectively keep two PHP versions per Drupal version or not at all for current builds. In the latter case, it may still be opted to exclude 8.3 for any new minor/major releases.

[tianon]

I was worried that dropping php8.3 was too aggressive, but I don't think it's very popular (and it probably shouldn't be, arguably), so even the "spicy" part of this should be pretty reasonable. 👍 ❤️

[tianon]

Do you think we should pre-emptively limit this to just versions less than 12, given that the 8.5+ requirement in 12+ looks pretty serious? I guess there's not really any harm in waiting to do that until we add our first 12+ version? (I'm mostly worried we'll forget 😂)

edit: putting an explicit link to https://www.drupal.org/project/drupal/issues/3537713, which is where things are looking pretty serious for 8.5+ in 12+

[jnoordsij]

If 12+ properly requires 8.5+ in their dependencies then composer should fail somewhere here, so that should be easy enough to spot:

drupal/Dockerfile.template

Lines 111 to 113 in 9dd7b9f

	composer create-project --no-interaction "drupal/recommended-project:$DRUPAL_VERSION" ./; \
	# https://github.com/docker-library/drupal/pull/266#issuecomment-2273985526
	composer check-platform-reqs; \

It could be worth considering to already allow 8.4 only on current 11.x minor builds and not any future ones, to preemptively limit the offered versions on any new minors and only offer them on reasonable request (or if you happen to remember and are in a particular good mood ;) ).

[yosifkit]

Suggested change

	if env.version | IN("10.5", "11.2") then
	"8.3"
	else empty end,
	if env.version | IN("10.5", "10.6", "11.2") then
	"8.3"
	else empty end,

We've already been publishing 10.6 builds on PHP 8.3. Even though it isn't the recommended version, they still support down to PHP 8.1. I think we should continue to try to support "up to two" PHP versions per Drupal version (when there are two valid PHP versions within DOI).

[tianon]

(force push is just a rebase for e8b27a2 & bf34400 😅)