build: bump ndn-cxx, ChronoSync, PSync dependencies

Also fix a few outdated URLs in docs

Change-Id: I4269ca53f55433568e8fd93eec497697c01b3c6d
diff --git a/README-dev.md b/README-dev.md
index 27aa479..060c556 100644
--- a/README-dev.md
+++ b/README-dev.md
@@ -1,7 +1,7 @@
 # Notes for NLSR developers
 
 If you are new to the NDN software community, please read the
-[Contributor's Guide](https://github.com/named-data/.github/blob/master/CONTRIBUTING.md).
+[Contributor's Guide](https://github.com/named-data/.github/blob/main/CONTRIBUTING.md).
 
 ## Licensing requirements