updated attribution

Author: llpeterson

README.rst

@@ -37,7 +37,7 @@ This book incorporates introductory and background content from:
 | *Title: Computer Networks: A Systems Approach*
 | *Authors: Larry Peterson and Bruce Davie*
 | *Source:* https://github.com/SystemsApproach/book
-| *License:* \ `CC BY-NC-ND 4.0 <https://creativecommons.org/licenses/by-nc-nd/4.0>`__
+| *License:* \ `CC BY 4.0 <https://creativecommons.org/licenses/by/4.0>`__
 
 Designations used by companies to distinguish their products are often
 claimed as trademarks or registered trademarks. In all instances in
@@ -93,7 +93,3 @@ Source <https://opensource.guide/how-to-contribute/>`__ guide. Among
 other things, you’ll learn about posting *Issues* that you’d like to see
 addressed, and issuing *Pull Requests* to merge your improvements back
 into GitHub.
-
-If you’d like to contribute and are looking for something that needs
-attention, see the `wiki <https://github.com/SystemsApproach/security/wiki>`__
-for the current TODO list.