Use old Hugo version for test build

.gitea/workflows/prod.yml

@@ -49,6 +49,11 @@ jobs:
     if: gitea.repository == 'gcg/schuelerzeitung'
     runs-on: act-runner-user
     steps:
+      - name: Setup Hugo
+        uses: https://github.com/peaceiris/actions-hugo@v3
+        with:
+          hugo-version: '0.123.0'
+          extended: true
       - name: Pull
         run: |
           git fetch --all