bump to 6.8.4-18.5

package.json

 {
   "name": "searchguard",
-  "version": "6.8.3-18.5",
+  "version": "6.8.4-18.5",
   "description": "Search Guard features for kibana",
   "main": "index.js",
   "homepage": "https://search-guard.com",

pom.xml

@@ -19,7 +19,7 @@
   <groupId>com.floragunn</groupId>
   <artifactId>search-guard-kibana-plugin</artifactId>
   <packaging>pom</packaging>
-  <version>6.8.3-18.5</version>
+  <version>6.8.4-18.5</version>
   <name>Search Guard Kibana Plugin</name>
   <description>Search Guard Kibana Plugin for Elasticsearch 6</description>
   <url>https://github.com/floragunncom/search-guard</url>