chore: remove internal downstream build references from README

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Valerii Svydenko <vsvydenk@redhat.com>

Author: svor

README.md

@@ -79,12 +79,6 @@ This repo contains several [actions](https://github.com/eclipse-che/che-plugin-r
 * [![PR](https://github.com/eclipse-che/che-plugin-registry/actions/workflows/pr-checks.yml/badge.svg)](https://github.com/eclipse-che/che-plugin-registry/actions/workflows/pr-checks.yml)
 * [![try in webIDE](https://github.com/eclipse-che/che-plugin-registry/actions/workflows/try-in-web-ide.yaml/badge.svg)](https://github.com/eclipse-che/che-plugin-registry/actions/workflows/try-in-web-ide.yaml)
 
-Downstream builds can be found at the link below, which is _internal to Red Hat_. Stable builds can be found by replacing the 3.x with a specific version like 3.2.  
-
-* [pluginregistry_3.x](https://main-jenkins-csb-crwqe.apps.ocp-c1.prod.psi.redhat.com/job/DS_CI/job/pluginregistry_3.x/)
-
-NOTE: The registry downstream is a fork of upstream, with different plugin content and support for restricted environments enabled by default.
-
 
 # License