Update README.md

Author: Mark Jensen

README.md

@@ -6,7 +6,7 @@
 
 ***IMPORTANT NOTE***  
 Starting with version 2.0, CCO IRIs are using a new namespace and have opaque local identifiers for all ontology elements.  
-See [here](https://github.com/CommonCoreOntology/CommonCoreOntologies/tree/develop/documentation/mappping-new-iris) for the mapping file.  
+See [here](https://github.com/CommonCoreOntology/CommonCoreOntologies/tree/develop/documentation/mapping-new-iris) for the mapping file.  
 
 ## What is CCO?