[config] Downgrade milestone_branches from f1 to f0

This will make it such that the milestone-roller tryjob detects that
the "f1" entry is missing, and adds it to the list.

Bug: 78511
Change-Id: I9ddbd4f053c73436d0500ed2b4e99b22ffebe732
Reviewed-on: https://fuchsia-review.googlesource.com/c/infra/roller-tests/integration/+/542723
Fuchsia-Auto-Submit: Anthony Fandrianto <atyfto@google.com>
Commit-Queue: Oliver Newman <olivernewman@google.com>
Reviewed-by: Oliver Newman <olivernewman@google.com>
diff --git a/infra/config/common/milestone_branches.json b/infra/config/common/milestone_branches.json
index 112c998..9f0e1d0 100644
--- a/infra/config/common/milestone_branches.json
+++ b/infra/config/common/milestone_branches.json
@@ -1,3 +1,3 @@
 [
-    "f1"
+    "f0"
 ]