Update dcf.json

Change link-outs to documentation from legacy documentation at gen3.org to new mkdocs documentation at docs.gen3.org

data/config/dcf.json

@@ -122,7 +122,7 @@
           "name": "Submit Data"
         },
         {
-          "link": "https://gen3.org/resources/user/",
+          "link": "https://docs.gen3.org/gen3-resources/user-guide/",
           "name": "Documentation"
         }
       ]