Update artifact-size-metrics.yml

.github/workflows/artifact-size-metrics.yml

@@ -103,4 +103,7 @@ jobs:
         if: ${{ !contains(github.event.pull_request.labels.*.name, 'acknowledge-artifact-size-increase') }}
         run: |
           cd build/reports/metrics
-          cat has-significant-change.txt | grep false || echo An artifact increased in size by more than allowed or a new artifact was created.
+          cat has-significant-change.txt | grep false || {
+            echo An artifact increased in size by more than allowed or a new artifact was created.
+            exit 1
+          }