Add arm support

[li-boxuan]

Closes #92

[li-boxuan]

Reason for this change: openjdk docker image is deprecated.
See https://hub.docker.com/_/openjdk

[li-boxuan]

I tested https://hub.docker.com/r/liboxuanhk/janusgraph/tags on my ARM machine locally, but it would be great if someone could test it on an AMD machine.

[FlorianHockmann]

I just skimmed over the changes and have some early comments:

1. I see that you only modified push-images.sh. Isn't it possible to also build the images locally via build-images.sh? It would be good if we could build all images first locally to inspect any changes we make.
2. I guess also testing the images won't work, via test-image.sh? Or could we maybe at least get the tests to work somehow via GH Actions?
3. You've changed the base image, so please also update the documented base image here: https://github.com/JanusGraph/janusgraph-docker#docker-tagging-policy
4. We're only maintaining versions 0.5 and higher so I wouldn't modify older images any more.

But thanks a lot for tackling this issue, @li-boxuan!

[li-boxuan]

Isn't it possible to also build the images locally via build-images.sh

We can, but then we cannot test it (due to docker/buildx#166), so it does not make too much sense to build without testing. With this PR, we build the AMD image and test it in build-images.sh. Then, we build a multi-arch image without testing and then push it in push-images.sh.

But thanks a lot for tackling this issue

I was debugging an integration test (JanusGraphSerializerBaseIT) but couldn't get it working. Then I realized it was because of the incompatibility between ARM (my machine) and AMD (officially built image). Now I can run the test with the ARM image.

[FlorianHockmann]

I still don't really like that push-images.sh now builds images itself and then pushes those directly as these images can differ from those that we've built and tested before, e.g., if we use different build-args or versions.
But I guess we have to live with that for now if we want ARM support.

I added two minor comments. Apart from that, this looks good to me.

[li-boxuan]

I still don't really like that push-images.sh now builds images itself and then pushes those directly as these images can differ from those that we've built and tested before, e.g., if we use different build-args or versions.

One way is to tag arm/amd differently. For example, we would have 0.6.2-arm and 0.6.2-amd instead of a single 0.6.2. I consider this even worse than what this PR does.

[FlorianHockmann]

One way is to tag arm/amd differently. For example, we would have 0.6.2-arm and 0.6.2-amd instead of a single 0.6.2. I consider this even worse than what this PR does.

Agreed, I also just wanted to mention this as a possible problem that we should keep in mind for the future, but still accepted the PR as I also came to the conclusion that it's the best option for now.