docs: add warning to main branch and link to levski

[ajcasagrande]

If your build fails due to your commit message not passing the build checks, please review the guidelines here: https://github.com/edgexfoundry/edgex-go/blob/main/.github/Contributing.md

PR Checklist

Please check if your PR fulfills the following requirements:

• I am not introducing a breaking change (if you are, flag in conventional commit message with BREAKING CHANGE: describing the break)
• I am not introducing a new dependency (add notes below if you are)
• [N/A] I have added unit tests for the new feature or bug fix (if not, why?)
• [N/A] I have fully tested (add details below) this the new feature or bug fix (if not, why?)
• [N/A] I have opened a PR for the related docs change (if not, why?)

Testing Instructions

N/A

New Dependency Instructions (If applicable)

[ChristianDarr-personal]

LGTM