docs: add commit ids for dependencies to README.md

refs: #4260

Change-Id: I096d5502a1cdc5fe712021fc0046d883a456173b

README.md

@@ -35,6 +35,13 @@ the following links:
 - [Getting Started with NLSR](http://named-data.net/doc/NLSR/current/GETTING-STARTED.html)
 - [GitHub NLSR repository](https://github.com/named-data/NLSR)
 
+Currently, NLSR is not using the latest version of the ndn-cxx library. Therefore, it is
+necessary to checkout the following versions of its dependencies:
+
+- ndn-cxx: b555b00c280b9c9ed46f24a1fbebc73b720601af
+- NFD: f4056d0242536f85b7d7b4de1b5ac50dad65c233
+- Chronosync: 097bb448f46b8bd9a5c1f431e824f8f6a169b650
+
 Additional information
 ----------------------
 
@@ -44,4 +51,4 @@ Additional information
 - [NLSR Mailing List Sign Up](https://listserv.memphis.edu/scripts/wa.exe?GETPW1)
 - [NLSR Mailing List](https://listserv.memphis.edu/scripts/wa.exe?SUBED1=NLSR-HELP-L&A=1)
 - [NLSR Mailing List Archives](https://listserv.memphis.edu/scripts/wa.exe?A0=NLSR-HELP-L)
-- [NLSR Developer's guide](https://github.com/named-data/NLSR/blob/developers-guide/NLSR-Developers-Guide.pdf)
+- [NLSR Developer's guide](https://github.com/named-data/NLSR/blob/developers-guide/NLSR-Developers-Guide.pdf)