Manage monotonic offsets correctly in y2020 localizer

Currently only supports a single pi, but expanding to pi[2-5] shouldn't
be difficult.

Change-Id: Ibed8bd5a59e1a5a9971e9b60c81da413c21b4f7e
diff --git a/y2020/control_loops/drivetrain/BUILD b/y2020/control_loops/drivetrain/BUILD
index 03d2dc2..1bd760f 100644
--- a/y2020/control_loops/drivetrain/BUILD
+++ b/y2020/control_loops/drivetrain/BUILD
@@ -59,6 +59,7 @@
     hdrs = ["localizer.h"],
     deps = [
         "//aos/containers:ring_buffer",
+        "//aos/network:message_bridge_server_fbs",
         "//frc971/control_loops:profiled_subsystem_fbs",
         "//frc971/control_loops/drivetrain:hybrid_ekf",
         "//frc971/control_loops/drivetrain:localizer",