Docs use unreleased release candidate instead of published version

[siddharthkp]

Describe the bug
Our docs deploy main branch which isn't the same as the latest published release from npm. Which means, when looking at the docs, you can't be sure that the props and examples will actually work in your application even when you're on the latest version.

In practice, primer.style/react points at the latest release candidate, not at the latest published version. We usually release a new path/minor version every couple of weeks, so the chances of you running in this are not low.

Related issue: There is no easy way to see docs for an old version of primer/react that your application might be using.

To Reproduce
Steps to reproduce the behavior:

1. Go to Tooltip examples
2. Copy the example into your application
3. It wouldn't work as documented because the latest Tooltip changes are in a release candidate and not published yet.

Expected behavior

1. primer.style/react should point at the latest published version, not the version from main.
2. Bonus: We should introduce a version switcher on the docs which can take you the published version for older versions (and the latest release candidate)