action: update container version

Author: maxux

.github/workflows/kernel.yaml

@@ -31,7 +31,7 @@ jobs:
   kernel:
     name: "Zero-OS Kernel Image (v4)"
     runs-on: ubuntu-latest
-    container: ubuntu-24.04
+    container: ubuntu:24.04
     steps:
       - name: Checkout code
         uses: actions/checkout@v1