ci: use stage branch for securesign/fbc (#1424)

Signed-off-by: Tomas Turek <tturek@redhat.com>

Author: osmman

.github/workflows/main.yml

@@ -124,6 +124,7 @@ jobs:
         uses: actions/checkout@v4
         with:
           repository: "securesign/fbc"
+          ref: stage
           path: fbc
 
       - name: Build catalog