Minor README improvements; fix outdated URLs

Change-Id: Ia57f83892471ad85a2301ba4c8ab3df144581000
diff --git a/manpages/conf.py b/manpages/conf.py
index 03438b4..a1263b8 100644
--- a/manpages/conf.py
+++ b/manpages/conf.py
@@ -7,7 +7,7 @@
 # https://www.sphinx-doc.org/en/master/usage/configuration.html#project-information
 
 project = 'NDN Essential Tools'
-copyright = 'Copyright © 2014-2022 Named Data Networking Project.'
+copyright = 'Copyright © 2014-2023 Named Data Networking Project.'
 author = 'Named Data Networking Project'
 
 # The short X.Y version.