Fixing Codecov badge to use the right link

It referred to Valloric/YouCompleteMe instead of ycm-core/YouCompleteMe

README.md

@@ -3,7 +3,7 @@ YouCompleteMe: a code-completion engine for Vim
 
 [![Gitter room](https://img.shields.io/gitter/room/Valloric/YouCompleteMe.svg)](https://gitter.im/Valloric/YouCompleteMe)
 [![Build status](https://dev.azure.com/YouCompleteMe/YCM/_apis/build/status/Valloric.YouCompleteMe?branchName=master)](https://dev.azure.com/YouCompleteMe/YCM/_build/latest?definitionId=1&branchName=master)
-[![Coverage status](https://img.shields.io/codecov/c/github/Valloric/YouCompleteMe/master.svg)](https://codecov.io/gh/Valloric/YouCompleteMe)
+[![Coverage status](https://img.shields.io/codecov/c/github/Valloric/YouCompleteMe/master.svg)](https://codecov.io/gh/ycm-core/YouCompleteMe)
 
 Help, Advice, Support
 ---------------------