Upgrade guava to 28.1-jre

Change-Id: I1d97ca1652f34c8307ce91771e9f1e3e89c89cf1

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index 003dd07..b6403e5 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -46,8 +46,8 @@
 
 maven_jar(
     name = "guava",
-    artifact = "com.google.guava:guava:28.0-jre",
-    sha1 = "54fed371b4b8a8cce1e94a9abd9620982d3aa54b",
+    artifact = "com.google.guava:guava:28.1-jre",
+    sha1 = "b0e91dcb6a44ffb6221b5027e12a5cb34b841145",
 )
 
 maven_jar(