Update Purdue details (add www domain)

Author: glentner

_data/rse-groups.yml

@@ -29,7 +29,7 @@
   url: https://phy.princeton.edu/
   institution: Princeton University
 - name: Center for Research Software Engineering
-  url: https://rcac.purdue.edu/rse
+  url: https://www.rcac.purdue.edu/rse
   institution: Purdue University
 - name: Data, Analytics & Research Computing at the GSB
   url: https://gsbresearchhub.stanford.edu/support-units/darc