Run in jenkinsci org only

Signed-off-by: Alexander Brandes <mc.cache@web.de>

Author: NotMyFault

.github/workflows/validate-renovate-config.yml

@@ -6,6 +6,7 @@ on:
       - master
 jobs:
   validate:
+    if: github.repository_owner == 'jenkinsci'
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1