Update README.md

Author: claucece

README.md

@@ -3,6 +3,10 @@
 ![MAYO-sage workflow](https://github.com/PQCMayo/MAYO-sage/actions/workflows/python-app.yml/badge.svg)
 [![License](https://img.shields.io/badge/License-Apache_2.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
 
+```
+This code is part of a NIST submission for the PQC signatures call.
+```
+
 This is the sage implementation of our MAYO scheme. Learn about it on our [website](https://pqmayo.org/).
 
 *Warning*: This code is a research prototype. Do not use it in production.