Fix outputting in build script

.gitea/workflows/build-base-image.yaml

@@ -1,10 +1,12 @@
 name: Build Docker Image for Actions
-on: [push, pull_request]
+on: [push]
 jobs:
   Check-Last-Time:
     runs-on: ubuntu-22.04
     env: 
       DEBIAN_FRONTEND: noninteractive
+    outputs:
+      last-time: ${{ steps.last-time.outputs.last-time }}
     steps:
       - name: Install jq
         run: |
@@ -16,6 +18,7 @@ jobs:
           | jq '.last_updated' 
           | xargs -i date --date {} +%s 
           | xargs -i expr $(date +%s) - {}
+          | xargs -i echo last-time={} >> $GITHUB_OUTPUT
   Build-Image:
     needs: [Check-Last-Time]
     if: needs.Check-Last-Time.outputs.last-time > 1