feat: add Starship feature to collection index

[tobiaschc]

What type of PR is this?

• Add a new dev container collection
• Update to an existing dev container collection
• Documentation/spec update
• Other containers.dev site update (UX, layout, etc)

Related Issues

• Related Issue #
• Closes #

Description

Add a new dev container feature to the collection. Although there are already features for Starship, mine provides an option to target a  starship.toml  file in a repository (a dotfiles one for example) or reference one locally. It also offers the opportunity to install a specified Nerd Font.

Check: https://github.com/tobiaschc/devcontainer-features

Collection checklist

If your PR contributes a new collection, please utilize this checklist:

• Collection name
• Maintainer name
• Maintainer contact link (i.e. link to a GitHub repo, email)
• Repository URL
• OCI Reference
• I acknowledge that this collection provides new functionality, distinct from the existing collections part of this index.