Remove EOL PHP versions

[ArjenMiedema]

Since it's been over a year ago that PHP 7.2 has been unsupported (and only a couple of days until the EOL for PHP 7.3), it's a good moment to say farewell to several outdated PHP versions in the Docker environment.

This means that the following PHP versions can be removed at this moment:

• PHP 5.6
• PHP 7.0
• PHP 7.1
• PHP 7.2

[esjdev]

What if working with a legacy project?

[peterjaap]

I agree with @esjdev, it shouldn't be necessary to remove these. We sometimes have legacy projects as well.

[ArjenMiedema]

If you have projects running on PHP 5.6 or PHP 7.0/7.1 your problem is a lot bigger than the fact that this Docker environment no longer supports it. These versions are end of life for more than 2 years now. So I still think that these versions can be removed. I could agree on keeping PHP 7.2 in there for now, but also that one is outdated for over a year now.

[JeroenBoersma]

I agree with @peterjaap and @esjdev on this, the main reason was to have flexibility to run older projects too.

We still onboard legacy projects which we need to upgrade.

I have looked into a more flexible way where you can add/disable them by config parameters, this is still WIP and a lot of WIP.

Good point/discussion of coarse