Generate Homebrew Formula based on existing one

[fengzhou-msft]

Currently we generate Homebrew formula based on a template.

From time to time Homewbrew team may help fix some issues such as Homebrew/homebrew-core#48846, fix for Xcode 11. We may not get notified well with such changes, and the template is not updated with the changes. A regeneration of formula based on the template will lose the changes.

A proposed solution is to generate the new formula based on existing one and only update the version of azure-cli, resource url and resource sha256.

[yonzhan]

Generate the new formula based on existing one.