add url of github cargo issue

diff --git a/nailing-cargo b/nailing-cargo
index b2e4d50639a14ad882d525e72f2ff2d5366d5f4c..6bbbce78bb423c7779110f5333460db11763f236 100755 (executable)
--- a/nailing-cargo
+++ b/nailing-cargo
@@ -27,6 +27,7 @@ set -e
 
 # Why do we need this ?
 #
+#  https://github.com/rust-lang/cargo/issues/6713
 #  https://stackoverflow.com/questions/33025887/how-to-use-a-local-unpublished-crate
 #  https://github.com/rust-lang/cargo/issues/1481