Update heroku-php-nginx for CGroupsv2

[usiegj00]

This buildpack fails on modern OCI runtimes with cgroupsv2.

[bauerpl]

@dzuelke -It appears that all tests have failed due to a 401 Unauthorized error, likely due to missing or incorrect HEROKU_API_KEY and HEROKU_APP_NAME config variables. Could you please verify if the secrets are set correctly? Your help would be really appreciated.

[dzuelke]

@dzuelke -It appears that all tests have failed due to a 401 Unauthorized error, likely due to missing or incorrect HEROKU_API_KEY and HEROKU_APP_NAME config variables. Could you please verify if the secrets are set correctly? Your help would be really appreciated.

Yes; the necessary GHA secrets aren't available for forks ;)

General feedback on this PR: I have been working on the same thing, so we can make it a race to see who's done sooner ;) But if you have time immediately and can finish it quickly...

1. please use a list of possible locations to read from and loop over them... the current approach is pretty crude
2. there need to be additional locations that get checked, since the current process may be in a different cgroup hierarchy
3. bin/heroku-php-apache2 needs exactly the same changes
4. ditto for bin/test
5. ditto for the profile.d script generated in support/build/composer
6. ditto for the profile.d script generated in support/build/php

[dzuelke]

Closing in favor of tracking issue #699