Upgrade gson to 2.8.0

Change-Id: Ib9bfd06e1c315ac2e0690a13559cc875a89c9376

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index e675980..0a471bb 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -16,8 +16,8 @@
 
 maven_jar(
     name = "gson",
-    artifact = "com.google.code.gson:gson:2.7",
-    sha1 = "751f548c85fa49f330cecbb1875893f971b33c4e",
+    artifact = "com.google.code.gson:gson:2.8.0",
+    sha1 = "c4ba5371a29ac9b2ad6129b1d39ea38750043eff",
 )
 
 maven_jar(