Bazel upgrade 0.8.0-rc4

Change-Id: I59c228ce2a7fe62d95b64e8b6bde0b8fc07f8641
diff --git a/aos/build/queues.bzl b/aos/build/queues.bzl
index 8696bac..9dd23bd 100644
--- a/aos/build/queues.bzl
+++ b/aos/build/queues.bzl
@@ -52,7 +52,7 @@
 def _q_deps_impl(ctx):
   transitive_q_files = ctx.files.srcs
   for dep in ctx.attr.deps:
-    transitive_q_files += dep.transitive_q_files
+    transitive_q_files = transitive_q_files + dep.transitive_q_files
   return struct(transitive_q_files = transitive_q_files)
 
 _q_deps = rule(