Build & publish Docker image using GitHub Workflow

[addianto]

Good day!

I created a new workflow to automate building Docker image and publishing it to Docker Hub.
It is also to resolve issue #93, as I noticed the images on Docker Hub are outdated.

I have tested the new workflow in a separate branch during development.
The successful workflow run log can be found at: https://github.com/addianto/spring-petclinic-rest/actions/runs/6611300030/job/17954895176

Please note that the workflow requires two GitHub Secrets (i.e., DOCKERHUB_USERNAME & DOCKERHUB_TOKEN).
I assume the project's maintainers do have access to the Docker Hub account that publishes the image in order to create the required GitHub Secrets.

[arey]

Thanks @addianto I will try to publish a new Docker image with your new workflow

[addianto]

You're welcome, @arey. 🙏 Don't forget to set up the required DOCKERHUB_TOKEN and DOCKERHUB_PASSWORD variables as repository secrets at this repository's settings, i.e. https://github.com/spring-petclinic/spring-petclinic-rest/settings/secrets/actions.

[arey]

I will switch to on: workflow_dispatch for manual testing

[arey]

The 3.0.2 is available right now: https://hub.docker.com/repository/docker/springcommunity/spring-petclinic-rest/general
I will revert my last commit

[arey]

We could generalize this workflow to all the main repositories