Fix loop for new line separted entries

Author: AnHeuermann

.github/workflows/build.yml

@@ -108,7 +108,8 @@ jobs:
         if: github.event_name != 'pull_request'
         shell: bash
         run: |
-          for img in ${{ needs.build.outputs.image }}; do
+          IMAGES="${{ needs.build.outputs.image }}"
+          for img in $IMAGES; do
             docker pull "$img"
           done