feature request: auto docker push

[cyberhck]

Hi there, I love your deployment process, I want to deploy your app in docker, I'd love if you could publish docker automatically.

I also use semantic-release for versioning, now.sh as lambda function, but in semantic-release, I also push my image to docker hub. Here's a sample: https://github.com/fossapps/MergeWhenReady

It'd be amazing if you could push to docker hub, and I'd just use the app by setting some env variable like so:

APP_ID=""
WEBHOOK_SECRET=""
BASE64_PRIVATE_KEY=""
GHE_HOST="github.private-domain.com"

Thanks, I'd be willing to help you out with this.

[donovanmuller]

This would also help with running this action in self-hosted runners and using a corporate HTTP proxy, where we currently cannot pass HTTP proxy build args. to Docker builds (see this feature request) and therefore cannot build the image when run.

I currently have to use the main branch to get around this.