Fix SUPERCOP url

README.md

@@ -8,7 +8,7 @@ schemes that are in the
 The goal of PQClean is to provide *standalone implementations* that 
 * can easily be integrated into libraries such as [liboqs](https://openquantumsafe.org/#liboqs) or [libpqcrypto](https://libpqcrypto.org/);
 * can efficiently upstream into higher-level protocol integration efforts such as [Open Quantum Safe](https://openquantumsafe.org/#integrations);
-* can easily be integrated into benchmarking frameworks such as [SUPERCOP](https://bench.cr.yp.to/supercop.shtml);
+* can easily be integrated into benchmarking frameworks such as [SUPERCOP](https://bench.cr.yp.to/supercop.html);
 * can easily be integrated into frameworks targeting embedded platforms such as [pqm4](https://github.com/mupq/pqm4);
 * are suitable starting points for architecture-specific optimized implementations;
 * are suitable starting points for evaluation of implementation security; and