TBR: todos: Add '/.jiri' to .gitignore in all repos.

Change-Id: I2d4e32c51906d3bb39b362584eedbc1434feb8f3
MultiPart: 25/28
PresubmitTest: none
diff --git a/.gitignore b/.gitignore
index eafd667..e39b0d5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,5 @@
+/.jiri
+#TODO(nlacasse): Get rid of .v23 below once v23->jiri transition is complete.
 /.v23
 /bin
 /creds