Update README.md

Author: Quentin Perez

README.md

@@ -1154,6 +1154,7 @@ $ scw inspect myserver | jq '.[0].public_ip.address'
 
 ### master (unreleased)
 
+# Add a warn message when using `ssh exec` on host without public ip nor gateway ([#171](https://github.com/scaleway/scaleway-cli/issues/171))
 * Support of `scw rmi` snapshot|volume ([#258](https://github.com/scaleway/scaleway-cli/issues/258))
 * Match bootscript/image with the good architecture ([#255](https://github.com/scaleway/scaleway-cli/issues/255))
 * Support of region/owner/arch in the cache file ([#255](https://github.com/scaleway/scaleway-cli/issues/255))