update affiliation to carbonplan (#252)

Author: jukent

portal/index.md

@@ -270,7 +270,7 @@ are open to anyone who wishes to participate. We publish
 
 **Anderson Banihirwe**
 <br/>
-[**NCAR**](https://ncar.ucar.edu)
+[**CarbonPlan**](https://carbonplan.org/)
 <br/>
 [@andersy005](https://github.com/andersy005)