Fixed typo

Author: aram356

README.md

@@ -91,7 +91,7 @@ git clone [email protected]:IABTechLab/trusted-server.git
 :information_source: Note that you’ll have to edit the following files for your setup:
 
 - fastly.toml (service ID, author, description) 
-- Potsi.toml (KV store ID names) 
+- potsi.toml (KV store ID names) 
 
 ### Build