Add missing include to static_vector.h

Hadn't noticed previously due to vector.h getting included via other
files.

Change-Id: I127d728b8d531b81b90aa169558f44286ba77339
Signed-off-by: James Kuszmaul <jabukuszmaul+collab@gmail.com>
diff --git a/aos/flatbuffers/static_vector.h b/aos/flatbuffers/static_vector.h
index 0aff48e..7349a8d 100644
--- a/aos/flatbuffers/static_vector.h
+++ b/aos/flatbuffers/static_vector.h
@@ -3,6 +3,7 @@
 #include <span>
 
 #include "flatbuffers/base.h"
+#include "flatbuffers/vector.h"
 #include "glog/logging.h"
 
 #include "aos/containers/inlined_vector.h"