Track main branch for 3pp

Jiri still tracks "master" by default, but the "master" branch is not
being kept up-to-date for 3pp.

Change-Id: I47a1457daa72b1b36b39b05fbabc4af394828d52
Reviewed-on: https://fuchsia-review.googlesource.com/c/manifest/+/925572
Reviewed-by: Catherine Duncan <catduncan@google.com>
diff --git a/infra b/infra
index 8645dc8..fc860ea 100644
--- a/infra
+++ b/infra
@@ -15,7 +15,8 @@
     <project name="fuchsia/3pp"
              path="fuchsia/3pp"
              remote="https://fuchsia.googlesource.com/infra/3pp"
-             gerrithost="https://fuchsia-review.googlesource.com"/>
+             gerrithost="https://fuchsia-review.googlesource.com"
+             remotebranch="main"/>
     <project name="fuchsia/infra"
              path="fuchsia/infra"
              remote="https://fuchsia.googlesource.com/infra/infra"