CI: Fix container image build workflow

Use Ubuntu Jammy images for Antelope image builds.

Author: priteau

.github/workflows/stackhpc-container-image-build.yml

@@ -45,7 +45,7 @@ jobs:
   generate-tag:
     name: Generate container image tag
     if: github.repository == 'stackhpc/stackhpc-kayobe-config'
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     permissions: {}
     outputs:
       datetime_tag: ${{ steps.datetime_tag.outputs.datetime_tag }}