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

[zedy-wj]

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

1. For the Github Action feature: We will remove two lines of code on container image and add GHA code after checkout step in the .github/workflow/azure-dev.yml file. (Shown as below)

2. For the Azd Devcontainer feature:

• Add the following code in devcontainer.json file.

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

and remove the relevant code for installing azd in devcontainer.json file.

"postCreateCommand": "curl -fsSL https://aka.ms/install-azd.sh | bash",

• Remove the relevant code for build Dockerfile in devcontainer.json file and remove Dockerfile under .devcontainer folder.

"build": {
	"dockerfile": "Dockerfile",
	"args": { 
		"VARIANT": "6.0-bullseye"
	}		
},

and add an image in devcontainer.json file.

"image": "mcr.microsoft.com/vscode/devcontainers/dotnet:0-6.0-bullseye",

@rajeshkamal5050 , @KSchlobohm , @nishanil for notification.

[KSchlobohm]

Thanks for the feedback @zedy-wj we've updated the content to support Dev Containers and a newer version of AZD in the latest PR #369.