Deploy using Dockerfile gives `The legacy builder is deprecated` warning about dokku HOT 4 CLOSED

Thats a warning from docker, not dokku. I think you probably want to look at the lines right after the first line of the error message:

remote: DEPRECATED: The legacy builder is deprecated and will be removed in a future release.
remote:             Install the buildx component to build images with BuildKit:
remote:             https://docs.docker.com/go/buildx/

It tells you to install buildx and links you to the docs for it. You can probably just run: apt install docker-buildx-plugin to fix it (thats how I have it on my system).

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Closing as there is a pull request open.

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Agreed its a warning from docker. I already have buildx installed (seems to be installed by default with docker desktop on my M2 mac) - I can e.g. docker buildx ls and get output.

Perhaps its how dokku invokes docker - some configuration or flag? Not sure what the aforementioned pull request does - as I say, I already have buildx installed so don't know what else to do to avoid the warning.

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The plugin might be installed on the engine side - I'm assuming you're running dokku inside of docker on Docker Desktop - but isn't installed in the container running Dokku. You'd need to apt install it inside that container so the docker cli has access to the plugin. The PR in question does that by default, which should fix the warning, but you'll need to manually install it now to get it working until I merge it and make a release.

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