Updates HAProxy to the 2.2-alpine tag

[stumpylog]

Updates the underlying HAProxy to the 2.2-alpine, which fixes #28 and closes #29 and closes #49. It goes a bit less far than GH-29

[yajo]

I'll add some small tests before merging, just to be sure this works as expected and to be able to merge things faster.

Sorry for the long wait and thanks for the contribution.

[pascalandy]

following big time!

[SuperSandro2000]

Bump?

[yajo]

This is quite outdated. Please rebase and fix conflicts.

[SuperSandro2000]

This is a single line fix. Not like it could be cherry picked into master.

[yajo]

I don't think the same:

1. It's not a fix because we have no bug there.
2. And this "single line" changes all the underlying docker image.
3. And in this time that has passed, we have set in place a test suite that would make me comfortable of merging it.

So, please rebase.

Otherwise, somebody could open a new PR superseding this one, which seems stale 🤷🏼‍♂️

[SuperSandro2000]

I have opened #49.

[stumpylog]

I found some time to rebase and fix the conflicts

[yajo]

Thanks! The tests seem happy, so I'll merge.

[yfhyou]

Did anyone come across this issue when testing this PR? #125