general: update unity location

Now that unity has moved to the cue-lang organisation, update its
location in codereview.cfg

Signed-off-by: Paul Jolly <paul@myitcv.io>
Change-Id: I9b1d9a379206fd5368eec371fb74bf41f89ec9d9
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/520530
Unity-Result: CUEcueckoo <cueckoo@cuelang.org>
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>

Author: myitcv

codereview.cfg

@@ -1,3 +1,3 @@
 gerrit: https://review.gerrithub.io/a/cue-lang/cue
 github: https://github.com/cue-lang/cue
-cue-unity: https://github.com/cue-sh/unity
+cue-unity: https://github.com/cue-lang/unity