term: add codereview.cfg

This will let git codereview rewrite issue references to the golang/go
repo. See https://golang.org/cl/4131 for details.

Change-Id: I5d5871b8570cdd448949a5a984027f909ab521a5
Reviewed-on: https://go-review.googlesource.com/c/term/+/352590
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
diff --git a/codereview.cfg b/codereview.cfg
new file mode 100644
index 0000000..3f8b14b
--- /dev/null
+++ b/codereview.cfg
@@ -0,0 +1 @@
+issuerepo: golang/go