DOCSP-22753 update Node.js version (#208)

Author: Dave Cuthbert

source/index.txt

@@ -17,7 +17,7 @@ MongoDB Shell (``mongosh``)
    :class: singlecol
 
 The |mdb-shell|, ``mongosh``, is a fully functional JavaScript and 
-Node.js 14.x |repl| environment for interacting with MongoDB 
+Node.js 16.x |repl| environment for interacting with MongoDB 
 deployments. You can use the |mdb-shell| to test queries and operations 
 directly with your database.