Correct peppermint command

README.md

@@ -15,6 +15,6 @@ That gets the ability to use firefox,wget, and to install docker-ce.
 Peppermint
 ==========
 sudo cp ZscalerRootCertificate-2048-SHA256.crt /usr/local/share/ca-certificates/
-sudo update-ca-certificate
+sudo update-ca-certificates
 
 That gets firefox and wget working.