feat: add new k3s plugin

[dmpe]

Summary

Add new plugin for k3s binary.

Description:

• Tool repo URL: https://github.com/k3s-io/k3s
• Plugin repo URL: https://github.com/dmpe/asdf-k3s

Checklist

• Format with scripts/format.bash
• Test locally with scripts/test_plugin.bash --file plugins/<your_new_plugin_name>
• Your plugin CI tests are green
  • Tip: use the plugin_test action from asdf-actions in your plugin CI
  • only for linux, mac14 github action runner did not worked (the project does not seem to support mac m1+)

[jthegedus]

Thanks