Update README.md (tinkerbell#133)

## Description


Remove Equinix Metal specific stability warning. This is inline with what has been done in other repos in the Tinkerbell org.

## Why is this needed



Fixes: #

## How Has This Been Tested?





## How are existing users impacted? What migration steps/scripts do we need?





## Checklist:

I have:

- [ ] updated the documentation and/or roadmap (if required)
- [ ] added unit or e2e tests
- [ ] provided instructions on how to upgrade

README.md

@@ -1,10 +1,6 @@
 # PBNJ
 
 ![For each commit and PR](https://github.com/tinkerbell/pbnj/workflows/For%20each%20commit%20and%20PR/badge.svg)
-![stability](https://img.shields.io/badge/Stability-Experimental-red.svg)
-
-> This repository is [Experimental](https://github.com/packethost/standards/blob/main/experimental-statement.md) meaning that it's based on untested ideas or techniques and not yet established or finalized or involves a radically new and innovative style!
-> This means that support is best effort (at best!) and we strongly encourage you to NOT use this in production.
 
 ## Description