invalid html anchor used in error message: CONTRIBUTING.md#prerequisites and missing description of necessary tools

[bmerkle]

please see the following error message. It uses a html anchor (prerequisites) which does not exists.
https://github.com/github/gh-aw/blob/main/CONTRIBUTING.md#prerequisites

Either describe the prerequisites in CONTRIBUTING.md e.g.

• node version
• go version
• other tools which are necessary and not installed by default, e.g. go deadcode tool needs to be installed explicitely

merklbe1@H69LST3:~/githubnext/gh-aw (main =)$ make deps
Error: Node.js version v18.19.1 is not supported.

This project requires Node.js 20 or higher.
Your current version: v18.19.1

Please upgrade Node.js and try again.

For installation instructions, see:
  https://github.com/github/gh-aw/blob/main/CONTRIBUTING.md#prerequisites

[pelikhan]

@copilot update the contributing instructions to use the devcontainer.json to configure a dev box. Generic dev environment are not supported.