The Usage Part in README.md Not Up-to-date

<img width="630" alt="bug" src="https://user-images.githubusercontent.com/96152068/151666570-17b231bd-cee8-4866-9a78-6cdb825abd3f.png">

The latest version is 0.6.0, but it's still _@v0.2.0_ in the readme file.

If I use _@v0.2.0_, I will get `jekyll 3.9.0 | Error:  404 - Not Found - Loading URL: https://codeload.github.com/pages-themes/primer/zip/v0.2.0` in a local test.