Added a new networking course (changes made) (#9696)

* add a new networking course

* Update courses/free-courses-en.md

Co-authored-by: Eric Hellman <eric@hellman.net>

---------

Co-authored-by: indic_gamer <channayyagarampalli@gmmail.com>
Co-authored-by: Eric Hellman <eric@hellman.net>

courses/free-courses-en.md

@@ -1127,6 +1127,7 @@
 
 ### Networking
 
+* [Computer Networking: A Top-Down Approach 8th edition](http://gaia.cs.umass.edu/kurose_ross/online_lectures.htm) - Jim Kurose, Keith Ross 
 * [Computer Networking Course](https://www.youtube.com/watch?v=qiQR5rTSshw) - Brian Farrell (FreeCodeCamp.org)
 * [Computer Networking Full Course - OSI Model Deep Dive with Real Life Examples](https://www.youtube.com/watch?v=IPvYjXCsTg8) - Kunal Kushwaha
 * [Computer Networks 5e](https://media.pearsoncmg.com/ph/streaming/esm/tanenbaum5e_videonotes/tanenbaum_videoNotes.html) - Andrew Tanenbaum, David Wetherall (Pearson)