TBR: pipe2browser: Add '/.jiri' to .gitignore in all repos.

Change-Id: I6e48c38f47844511f459c041fb64bc1cbfe90a2e
MultiPart: 22/28
PresubmitTest: none
diff --git a/.gitignore b/.gitignore
index ea4c018..717341e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,5 @@
+/.jiri
+#TODO(nlacasse): Get rid of .v23 below once v23->jiri transition is complete.
 browser/build.js*
 browser/index.html
 browser/third-party