fix: Proper build target for local Docker Compose

[Wirone]

Bug introduced in #7782, I probably had compose.override.yml and did not encounter this before. Now I wanted to check lower PHP versions because #7777 stopped working for <8.1 and got an error during build.

To make sure it won't happen again, I've added new CI workflow that will test Docker Compose builds when PR has Docker-related changes, on master branch push and once a day as a scheduled pipeline.

I've moved current Docker workflow to "Release" workflow, we can later add more jobs that should happen on tags (like publishing official page).

[coveralls]

coverage: 94.769%. remained the same
when pulling 80743f4 on Wirone:codito/fix-docker-compose-build
into 4ab8fc4 on PHP-CS-Fixer:master.

[Wirone]

@keradus @julienfalque Actually we could use docker compose for running every other CI / SA job on each PHP version, instead of using shivammathur/setup-php. With this approach we would have exact same runtime in CI as locally for development and in real-world where official Docker images are used. But this is separate topic that we should discuss and implement only if we agree on it 😉.

[julienfalque]

Yeah IMO it's better because, as you said, the runtime in dev and CI is (almost) exactly the same, even if there will always be some small differences. That's what we did at one of my previous jobs and it led to easier CI setup and much less CI specific failures.

However this requires a good caching setup for Docker images to avoid rebuilding those everytime. My experience is based on Bitbucket Pipelines, which had a caching system that could only store one cache version, so it worked well as long as the Docker setup didn't change at all, in which case the images were rebuilt on every job until the cache expired or was manually removed. I don't know how easy that would be on GitHub.

[Wirone]

That's why I said it's something to do in a separate PR 😉. For now let's just fix local build and make sure it's always buildable.