Update deadline and rename assignment 4 - stp

Signed-off-by: Dragos Iulian Argint <dragosargint21@gmail.com>

Author: dragosargint

Documentation/teaching/so2/assign4-transport-protocol.rst renamed to Documentation/teaching/so2/assign4.b-transport-protocol.rst

@@ -1,8 +1,8 @@
 =====================================
-Assignment 4 - SO2 Transport Protocol
+Assignment 4.b - SO2 Transport Protocol
 =====================================
 
-- Deadline: :command:`Monday, May, 31, 2021, 23:00`
+- Deadline: :command:`Tuesday, 24 May 2022, 23:00`
 - This assignment can be made in teams (max 2). Only one of them must submit the assignment, and the names of the student should be listed in a README file.
 
 Implement a simple datagram transport protocol - STP (*SO2 Transport Protocol*).