Dockerfile improvements and automatic Github Actions Docker builds

[sethforprivacy]

Feel free to take or leave anything you like here, but wanted to push upstream some minor optimizations to the Dockerfile along with an easy way to get automatic Docker image builds via Github Actions, for both amd64 and arm64.

The main part you may not want is pinning Docker images to releases/tags as I've done here, if not I'm happy to modify the PR to remove that aspect, but I personally like that for two reasons:

1. It ensures that a bad push to master doesn't publish broken images automatically
2. It adds a proper Docker tag that can be used, i.e. this will automatically tag the images with the short-sha, latest, and v0.0.9

[sethforprivacy]

You can see/test example images here:

https://github.com/sethforprivacy/ohttp-relay/pkgs/container/ohttp-relay

[DanGould]

We're doing some breaking changes with the upcoming release. I want to make sure all is well with the release before we make it so easy to deploy.

The one thing that sticks out as desirable before this is merged is to use local source code instead of the repository in the Dockerfile (RUN git clone --branch ${BRANCH} https://github.com/payjoin/ohttp-relay.git /tmp/build)

[sethforprivacy]

We're doing some breaking changes with the upcoming release. I want to make sure all is well with the release before we make it so easy to deploy.

The one thing that sticks out as desirable before this is merged is to use local source code instead of the repository in the Dockerfile (RUN git clone --branch ${BRANCH} https://github.com/payjoin/ohttp-relay.git /tmp/build)

Ah, yes, it makes sense to do that in my own repo but not here :)

Will push a commit momentarily to change that back!

[benalleng]

Now that we have 0.0.10 released do we think it's the right time to move forward with this?

[benalleng]

Closed as migrated to payjoin/rust-payjoin#1244