Bazel: Remove unnecessary plugin_name parameter

Change-Id: I6a20912558626266eaae141e22e00494ae8aae0d

BUILD

diff --git a/BUILD b/BUILD
index 6379a0d..9fd9c55 100644
--- a/BUILD
+++ b/BUILD
@@ -37,7 +37,6 @@
 polygerrit_plugin(
     name = "rv-reviewers",
     app = "reviewers-bundle.js",
-    plugin_name = "rv-reviewers",
 )
 
 rollup_bundle(