Fix buck tests

Wiremock dependency was dropped erroneously

Change-Id: Ie0a2c48e0e1fcf3f8e2c9c609dbdf1e3eceb0d02

BUCK

diff --git a/BUCK b/BUCK
index 1126b12..52aaea7 100644
--- a/BUCK
+++ b/BUCK
@@ -7,6 +7,7 @@
 
 TEST_DEPS = GERRIT_PLUGIN_API + GERRIT_TESTS + [
   ':sync-index__plugin',
+  ':wiremock',
   ':mockito',
 ]