diff --git a/.github/workflows/testcore12.yml b/.github/workflows/testcore12.yml
index a07822f..a87e093 100644
--- a/.github/workflows/testcore12.yml
+++ b/.github/workflows/testcore12.yml
@@ -6,6 +6,7 @@ on:
 jobs:
   dummy:
     name: "dummy v12 (disabled on main) to allow creation of badges for other branches"
+    runs-on: ubuntu-latest
     steps:
       - name: "Checkout"
         uses: actions/checkout@v6