Update README.md

hw5/README.md

 # Out-of-Core Group By Aggregate
 
-*Due 6/1/19 11:59 PM*
+*Due 6/5/19 11:59 PM*
 
 In this assignment, you will implement an out-of-core
 version of the group by aggregate (aggregation by key)
 seen in lecture. You will have a set memory limit and 
 you will have to count the number of times a string shows 
 up in an iterator. Your program should work for any limit 
-> 20.
+less than 20.
 
 ## Getting Started
 First, pull the most recent changes from the cmsc13600-public repository: