Support creating builder from docker context

[ngraef]

In a setup with a remote daemon, I have the environment variables DOCKER_HOST, DOCKER_CERT_PATH, and DOCKER_TLS_VERIFY set on the runner. Using this action gives me the following error:

🔨 Creating a new builder instance...
/usr/bin/docker buildx create --name builder-build-2 --driver docker-container --use
could not create a builder instance with TLS data loaded from environment. Please use `docker context create <context-name>` to create a context for current environment and then create a builder instance with `docker buildx create <context-name>`
##[error]The process '/usr/bin/docker' failed with exit code 1

I can run docker context create <context-name>, but there's no way to tell this action to use that context. Is this something you would consider supporting?

[crazy-max]

@ngraef

but there's no way to tell this action to use that context. Is this something you would consider supporting?

Can you try with this:

      -
        name: Set up Docker Buildx
        uses: crazy-max/docker-setup-buildx-action@add-context-input
        with:
          endpoint: mycontext

You can also use the DOCKER_CONTEXT env var:

      -
        name: Set up Docker Buildx
        uses: docker/setup-buildx-action@master
        env:
          DOCKER_CONTEXT: mycontext

[ngraef]

Thanks @crazy-max!