Add error message for git-ref script mismatch

Author: jonpugh

.github/workflows/scripts.tests.yml

@@ -79,5 +79,6 @@ jobs:
         REF=$(git-ref)
         echo "Current ref: $REF" >> $GITHUB_STEP_SUMMARY
         if [[ "$REF" != "${{ github.head_ref }}" ]]; then 
+          echo "Output of git-ref script ($REF) does not match github.head_ref (${{ github.head_ref }})
           exit 1; 
         fi