Depend on config rule instead of file.

The aos_config rule used to require you to depend on {name}.json to get
the output.  That was weird and hid private/testonly/etc.  Instead,
depend on the rule directly.

Change-Id: I1596a6c1f44b246a0db1bbc562468530a0b69614
diff --git a/y2020/control_loops/superstructure/BUILD b/y2020/control_loops/superstructure/BUILD
index 4534404..e97fb12 100644
--- a/y2020/control_loops/superstructure/BUILD
+++ b/y2020/control_loops/superstructure/BUILD
@@ -88,7 +88,7 @@
         "superstructure_lib_test.cc",
     ],
     data = [
-        "//y2020:config.json",
+        "//y2020:config",
     ],
     deps = [
         ":superstructure_goal_fbs",