Include AUTHORS file in releases

It is critical for downstream users to have documented copyright information in the software package that they download.

BUILD

diff --git a/BUILD b/BUILD
index b87a792..8401117 100644
--- a/BUILD
+++ b/BUILD
@@ -5,6 +5,7 @@
 filegroup(
     name = "distribution",
     srcs = [
+        "AUTHORS",
         "BUILD",
         "LICENSE",
         "//java:srcs",