Update openrefine link to git

Author: Chris Erdmann

_extras/discuss.md

@@ -8,4 +8,4 @@ There are many ways to discuss Library Carpentry lessons:
 - Join our [Slack organisation](https://swc-slack-invite.herokuapp.com/) and #libraries channel.
 - Stay in touch with our [Topicbox Group](https://carpentries.topicbox.com/groups/discuss-library-carpentry).
 - Follow updates on [Twitter](https://twitter.com/LibCarpentry).
-- Make a suggestion or correct an error by [raising an Issue](https://github.com/LibraryCarpentry/lc-open-refine/issues).
+- Make a suggestion or correct an error by [raising an Issue](https://github.com/LibraryCarpentry/lc-git/issues).