add recurring Community Call ICS

Author: joeyaiello

CommunityCall/README.md

@@ -1,4 +1,7 @@
-# PowerShell Community Call
+# PowerShell Core Community Call
+
+The PowerShell Core Community Call is held on the 3rd Thursday of every month.
+Use [this ICS file](RecurringCommunityCall.ics) (right-click Raw -> Save Target/Link As in order to download the file) to put this recurring event on your calendar. 
 
 ## Notes