Upgrade guava to 27.1-jre

Since 27.0-jre guava has a runtime dependency on failureaccess. See the
release notes for 27.0 [1] and 27.0.1 [2] for further details.

[1] https://github.com/google/guava/releases/tag/v27.0
[2] https://github.com/google/guava/releases/tag/v27.0.1

Change-Id: I10b3c012271b0bd55fc8b3bdd3f568131ab1dbdf

lib/BUILD

diff --git a/lib/BUILD b/lib/BUILD
index 9aef1e0..a2dc687 100644
--- a/lib/BUILD
+++ b/lib/BUILD
@@ -19,5 +19,6 @@
     "servlet-api_3_0",
     "gson",
     "guava",
+    "guava-failureaccess",
     "prettify",
 ]]