Docker compose seems to be outdated

[hellward]

The docker image for app seems to be deprecated. Following readme instructions results in PHP version error:

composer install --no-interaction --no-scripts
No composer.lock file present. Updating dependencies to latest instead of installing from lock file. See https://getcomposer.org/install for more information.
Loading composer repositories with package information
Updating dependencies
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - Root composer.json requires php ^8.1 but your php version (8.0.18) does not satisfy that requirement.
  Problem 2
    - sylius/sylius[v1.14.0, ..., v1.14.1] require php ^8.1 -> your php version (8.0.18) does not satisfy that requirement.
    - Root composer.json requires sylius/sylius ~1.14.0 -> satisfiable by sylius/sylius[v1.14.0, v1.14.1].

make: *** [Makefile:14: install] Error 2```