002: fix link to spec

PR-URL: nodejs#45
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Trevor Norris <trev.norris@gmail.com>
Reviewed-By: Bradley Farias <bradley.meck@gmail.com>

Author: chicoxyzzy

002-es6-modules.md

@@ -27,7 +27,7 @@ The intent of this standard is to:
 ## 2. Related
 
 
-[ECMA262](tc39.github.io/ecma262/) discusses the syntax and semantics of
+[ECMA262](https://tc39.github.io/ecma262/) discusses the syntax and semantics of
 related syntax, and introduces:
 
 ### 2.1. Types