Disable stale bot for forks (#2390)

diff --git a/.github/workflows/stale.yml b/.github/workflows/stale.yml
index 7c86904..a6c2aa8 100644
--- a/.github/workflows/stale.yml
+++ b/.github/workflows/stale.yml
@@ -12,7 +12,7 @@
 
 jobs:
   stale:
-
+    if: github.repository == 'apache/solr'
     runs-on: ubuntu-latest
     permissions:
       pull-requests: write