Suggestion: Add link to devcontainers example

[beta-tank]

I eventually got tired of manually configuring the toolchain and environment for building ZMK, so I created a repository to help build ZMK using your own configuration. It utilizes Devcontainers and GitHub Codespaces, requiring zero local machine configuration for firmware building. It also includes CI builds, similar to other configuration repositories.

If you think this is useful, you can find it here: https://github.com/beta-tank/zmk-config-devcontainer

[mctechnology17]

Thanks for your suggestion, it looks interesting and I'll add it to the next PR!