feat(postfix-exporter): releasing tagged postfix exporter images

[outofrange]

Added release version tags to postfix-exporter image builds in tag workflows.

Moving buildx-setup action from build-postfix-exporter action to Build_PostfixExporter job, so version env vars are available for defining image tags.
Also added buildx-setup action to the job in master branch as well, so build environment is still properly set up (since the action itself doesn't do it anymore).

Updated mail Helm Chart to use metrics image version through Chart AppVersion.

Fixes #264

[outofrange]

Todo:

• Setting postfix-exporter version tag in Helm chart releases

[outofrange]

@bokysan I tried testing this by pushing a tag to my fork, but the job fails because I haven't set up variables / secrets, pages, registry, ... in my fork.

Are the changes small enough for you to verify without?

[bokysan]

I'll check it out and merge when I'm at the keyboard.

Regarding version tags - there was one ticket that somebody had issues (I don't remember now if he needednv or without) so we're tagging for both. Since both images are the same, I didn't see any harm in it.

[outofrange]

Great, thanks!

I found #216 reporting an issue resulting from this, where helm search repo can get confusing as well.

Looking at your comment from back then in that issue, the reasoning seems to have been related to the fact that Helm expects X.Y.Z SemVer format, without the v prefix.
But I'm not sure if you didn't refer to a different issue, since #216 alone doesn't explain why the Helm chart with vX.Y.Z is then still being released.

Judging from other charts I use, from projects that release v-prefixed tags, releasing the Chart as X.Y.Z, with an AppVersion like vX.Y.Z is a common approach.

If I'm not mistaken, releasing Charts to OCI registries instead of Helm HTTP Repositories (which would be a nice addition at some point) would not only expect a non-prefixed version, but actually blocks prefixed versions from being pushed - but could have been another tool in our pipeline complaining about this as well, not sure anymore.

I'll see if this still feels icky later in the day and if I didn't forget about it already, and open an issue for further discussions :)

[bokysan]

Can you check the one comment above, please?