Add changelog entry

Author: will-in-wi

CHANGELOG.md

@@ -8,6 +8,7 @@ appear at the top.
   * Your contribution here!
   * [#455](https://github.com/capistrano/sshkit/pull/455): Ensure UUID of commands are stable in logging - [@lazyatom](https://github.com/lazyatom)
   * [#453](https://github.com/capistrano/sshkit/pull/453): `as` and `within` now properly escape their user/group/path arguments, and the command nested within an `as` block is now properly escaped before passing to `sh -c`. In the unlikely case that you were manually escaping commands passed to SSHKit as a workaround, you will no longer need to do this. See [#458](https://github.com/capistrano/sshkit/issues/458) for examples of what has been fixed. - [@grosser](https://github.com/grosser)
+  * [#460](https://github.com/capistrano/sshkit/pull/460): Handle IPv6 addresses without port - [@will-in-wi](https://github.com/will-in-wi)
 
 ## [1.18.2][] (2019-02-03)