Adding a new installation method to the README

[lunrenyi]

• Hi, we have implemented a lightweight package manager using shell and awk. It helps you download dust release packages from the internet and extract them into a unified directory for management, without requiring root permissions.

• I mean, can the installation method provided by x-cmd be added to the dust README?

  # eval "$(curl https://get.x-cmd.com)"    # Install the x command
  x env use dust
  

• dust demo: x-cmd recorded a demo and article for dust

Looking forward to your reply :) !