Updating/work-with this template for Azd Devcontainer feature.

[v-xuto]

We are updating this template to support new features in Azd Devcontainer.

For the Azd Devcontainer feature:
We will remove dockerfile in .devcontainer folder and add the following code in devcontainer.json file,

"ghcr.io/azure/azure-dev/azd:latest": {}

remove the relevant code for installing azd in .devcontainer/Dockerfile file.

RUN curl -fsSL https://aka.ms/install-azd.sh | bash \

and image also need to be add instead of build.

@rajeshkamal5050, @aarthiem for notification.