Add required podman version to the documentation

[mkristian]

I am new to pidman and new to tjus colkection. Yesterday it took me quite some time to figure out my problem, just to find that my podman version is too old for the latest collection here. But I was not able to find out which version I need to pick that works with my podman version.

Since I do not know which podman version the latest code requires I am not even able to prepare a PR.

[sshnaidm]

@mkristian Currently in CI it runs on Podman versions 4.6.2 and 3.4.4 due to limitations in Ubuntu Github runners. So we can be sure it works for them at least. If you have Centos7 and version 1.6.x it's better to use older collection versions. for example 1.11.0. TBH I don't keep full support matrix for all Podman versions, the collection is trying to support the newest Podman versions supposing you need to use the latest. The previous versions are supported in best effort.
The full support matrix will require much more effort and because this is community project I don't think it's going to be done soon. Otherwise you have ideas how to organize this easily.

[mkristian]

@sshnaidm

Interesting that the CI is not using podman5 maybe I can contribute some testcases using my usecase below. ( Not sure if I can make for it).

Just to demonstrate the problem I had: the quadlet config in in podman-5.0.3 allows

Pod=pod-name

But in podman-4.9.3 this does not exists.

Now the collection just happily created this and since I am new to quadlets it took a while to figure out that it is my podman version. In the end I switched to the latest non-LTS ubuntu version which comes with podman-5.0.3 since I was not able to figure out the collection version to use to be inline with the quadlet implementation of podman-4.9.3.

In short it is the quadlet implementation of podman which created my problem.

So I see your point of not being able to keep track of such compatibility matrix.

[sshnaidm]

@mkristian I see, that's a real pain, because Podman adds more and more Quadlet options every minor version. I decided here to stick always to the latest. One is not supposed to use minor 5 versions actually, but I expect a lot of distros to not update it quickly. TBH I didn't find a good solution, seems like problem of transient period. I don't want to pollute the code with versions comparisons, that's for sure. If you have more convenient solution, you're welcome to bring it up.
We don't test on v5 in CI, because it's not in ubuntu podman repos on 22.04. Actually we need a job to build the Podman from sources (last released and maybe latest main) and test it. I couldn't get to it yet.