Fix job configuration by ensuring 'runs-on' is specified for both main-job and post-job

.github/workflows/orchestratorci.yaml

@@ -10,11 +10,13 @@ on:
 
 jobs:
   main-job:
+    runs-on: gitea-orchestrator
     steps:
       - name: Provisioning
         run: |
           echo "Provisioning with spec: ${{ inputs.spec }}"
   post-job:
+    runs-on: gitea-orchestrator
     needs: main-job
     if: always()
     steps: