Bump plugin API to 3.0.16

Update in Docker image too.

Change-Id: I7d931865608dbebb8a99f33684d8b9667b4a9ac8

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index 31b9291..c047530 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "a029d8e41d6211c8b23052aa0a0c2c7649577e85",
+    commit = "a88174652e6f853ead5bbc5dacc1030dbb2d50c3",
     #local_path = "/home/<user>/projects/bazlets",
 )
 

test/docker/gerrit/Dockerfile

diff --git a/test/docker/gerrit/Dockerfile b/test/docker/gerrit/Dockerfile
index bebe667..b9d1715 100755
--- a/test/docker/gerrit/Dockerfile
+++ b/test/docker/gerrit/Dockerfile
@@ -1,4 +1,4 @@
-FROM gerritcodereview/gerrit:3.0.15-ubuntu18
+FROM gerritcodereview/gerrit:3.0.16-ubuntu18
 
 USER root