Publish container app yaml specification

[jason-berk-k1x]

Please provide us with the following information:

This issue is a: (mark with an x)

• [x] bug report -> please search issues before submitting
• [x] documentation issue or request
• [ ] regression (a behavior that used to work and stopped in a new release)

Issue description

we need the YAML specification for using the --yaml flag with az containerapp

Additional context

discussed here: https://github.com/microsoft/azure-container-apps/issues/9 requested again here:https://github.com/microsoft/azure-container-apps/issues/15 (but closed without actually solving the problem)

[anthonychu]

YAML has the same schema as JSON and is documented here:

• Apps
• Jobs

[jason-berk-k1x]

sure, but I'm interested in getting better support in VS Code. Right now, it just thinks I'm editing a yaml file....there's no JSON Schema