eliminate unintended exit with non-zero codes

.github/workflows/jitpack-build.yml

@@ -36,7 +36,7 @@ jobs:
               exit 0
             else
               echo "Attempt $((COUNTER+1)) failed with status $HTTP_STATUS: Tag not found yet. Retrying in $RETRY_DELAY seconds..."
-              ((COUNTER++))
+              COUNTER=$((COUNTER+1))
               sleep $RETRY_DELAY
             fi
           done